As I have mentioned in the past, I maintain a list of links to the histories of individual allotment sites.
https://bkthisandthat.org.uk/links-to-allotment-site-histories/Around this time of year I check each link to make sure that it still exists. I also look out for new histories that I can add to the list.
If your allotment site has a website with a history on it then I would be pleased to know about it.
Thanks.
Brian