There is some misunderstanding of what OLIO is by some posters I think.
However, I do agree with you that he expects a large amount of food, takes it for granted, and shows no gratitude.
Could you perhaps:
i) take less from the supermarket or whatever place you generally collect from if you are finding it hard to distribute it all
ii) speak to mother & toddler groups, other friends and neighbours to see if there are needy folk nearby who are unaware of OLIO and get them to sign up
iii) give a lot less to your neighbour as a result of i or ii above, but don't be too blunt as it's best not to risk antagonising him if neither of you is moving house!