Should she chip in?

In the UK it is usual that the fence is the responsibility of the householder, who, looking from the front of the house has the fence to the left side. Also it’s a general rule that if the fence posts sit in your hardy then it’s your fence. But these are only general rules and there are exceptions which can be checked with the Land Registry.

Explain to the neighbour that she would have to pay for the fence on the other side so can't afford both sides.

No, whether she can afford it or not is irrelevant. What happens when the fence that's her responsibility needs replacing? She should keep her money for when she needs it. I too think the neighbours have a cheek, it's their responsibility and no one else's. I have fully fenced my garden on all sides as I have dogs but the fence is on my land, my side of the boundary.

Having good relations with neighbours is worth its weight in gold. It’s important not to up the ante on this. The neighbours asked - that’s done now so what’s important is to deal with that whilst keeping on good terms. A polite refusal is all that’s required. Would I have asked? No but I’ve no money worries. Would I have given half if asked? Yes again because I could afford it, would be grateful that the fence was going to be improved and glad someone else was going to arrange to have it done. In the great scheme of unacceptable neighbour behaviour this ranks very low.

We didn't ask and our neighbours nd certainly didn't expect them to offer when we replaced 50 ft of concrete post and wood panel fencing. DH painted both sides of each panel before slotting them in, as the maintenance of that boundry is our responsibility as shown on the deeds.
We asked permission of the neighbours the other side to paint our side of their fence to match and it was freely given.
I think the OP's neighbours have a cheek.

There’s no need to criticise the neighbours for asking. As for who can afford what- we don’t know about that, just assumptions. They’ve asked by text do it’s fine to reply by text and leave it at that. If they are fine as neighbours, then keep it low key and maintain good relations

What happens in other countries is interesting, but it’s not relevant. If it’s the neighbours’ fence it is their sole responsibility to maintain it. As they can obviously well afford it, perhaps they don’t realise this (or perhaps they’re just trying their luck!). For the sake of neighbourly relations, your DD needs to keep it friendly, but stand firm on not paying, especially in her financial position. Could she perhaps make the situation clear to them by saying that she’s actually saving for work on her own fence?

We recently replaced a fence. It was established that it was ours and we didn’t expect, or ask, for a contribution .
Our neighbours didn’t offer and we are still on good terms with them.
I suppose there is no harm asking but there is no harm in refusing either. There is also no shame, IMO, in letting them know she can’t afford it.

What will happen when your DD’s fence on the other side needs replacement. Will DD be able to ask neighbours on the other side for a contribution? The whole thing is ridiculous, the grasping neighbours are chancers as Baggs said. It is all very well offering to help with someone else’s fence, different thing entirely being asked outright.

The neighbours are chancers. I think they are also being unkind putting this kind of pressure on your DD.

In Canada, if you want to build a fence on your property then the cost is yours. If the fence it built on the property line, then both property owners equal partners and must come to an agreement.

In certain neighbourhoods there may be bylaws regarding fence types and heights, so your daughter should check her local rules. She may be under no obligation to chip in, but if she enjoys the future use of the fence then perhaps she should.

Remember the old saying that good fences make good neighbours{smile}

I have a friend who agreed to that and then their neighbours decide the whole fence needed replacing and with far more expensive wood than the original.

Having agreed, she was too shy to say 'no' and is still paying it off in installments. Meanwhile, the neighbours have just put their house up for sale.

Grrrrrrr.

Here in Australia the cost of a new fence has to be shared. Apparently the biggest cause of neighbour disputes is about fencing.

When we replaced our fence our neighbours chipped in without us asking them. I thought it was a lovely gesture.

If its not legally her fence and she is short of money looking after 2 children on her own why should she contribute? Her neighbours sound cheeky and rather horrible!

Yes I agree with Septimia good relationships with neighbours are important.

No, sorry. Their fence, their responsibility. I'm surprised they had the cheek to ask, especially knowing she's a single parent.

Your daughter has no obligation to pay anything toward the cost of the fence if the boundry is the neighbours responsibilty. This will show on the deeds.

nope its their fence..maybe offer in man hours or as a tea lady while the work is being Done? i replaced a fence on the side that wasn't mine but thats because i have dogs and its my responsibility to keep them in my garden. Or like septimia says new plants or an amount she can afford

If it's their fence, she's under no obligation to contribute. However, it depends on her financial situation, the neighbours' ability to fund the whole fence themselves (it sounds as if they can), how friendly she is with the neighbours and whether she thinks it important to maintain a good relationship with them.
If she feels that she can contribute, and is willing to, perhaps she could suggest an amount that she can afford. Otherwise, maybe she can offer something else (new plants?) instead.