Getting my affairs in order

I work for an undertaker. A lot of funeral plans cover the cost of the actual funeral but not things like service sheets, catering, headstone etc which can come to quite a lot if you have them. . Also some plans are for a fixed amount, which may not be enough, and others cover the cost of specific parts of the funeral based on today's cost, and guarrantee to cover those items whatever they cost in the future.
Quoted undertaker's fees vary as to what they include, most cover standard coffin, hearse, and bearers, but some of the apparently cheap ones charge extra for these items! Also, when an undertaker quotes his fee, it does not include what they call 'disbursements' which are things that they might arrange for you but are provided by others eg the cost of burial (cemetery fees, grave digger) or cremation, either of which cost about £650-£900, limousines to transport mourners - up to £200 each, notices in paper, flowers, service sheets, celebrant, music/visual display catering, etc. I was shocked to discover that if you have a Cof E church service there is also the local minister fee, and a pcc and a diocesan fee, total about £400. To be buried in a church graveyard you have to pay for the plot and a gravedigger as above, and to bury cremated remains there is also a fee of several hundred pounds. Church Organ and bells extra. Did you know they ring one toll of the bell for every year of life? Green burials may be cheaper, there is no obligation to have a coffin (just a shroud) for a burial but you still pay for the plot.
I have started writing my own service with a view to getting it printed in advance, someone will have to write the date of my passing on by hand!

This is most helpful, thanks.

I worry about the financial stuff if DH goes first. He's always looked after us well in that respect and I've mostly left the long term stuff up to him. On a few occasions I've made him sit down and explain it all to me but he runs out of patience before I've got to grips with it all. Luckily my DD is an accountant so I'm hoping she'll be able to sort it out if the time comes.