...are there requirements about space, briefing customers, extra insurance, NoTams etc.
There will be a lot of people about and animals, is it left up to me to decide how to run it and the best landing sites etc, or are there rules.
There are lots of rules and requirements.
Have a look at CAP768 -
Chap.21, Annex 1 – Site Surveying
Chap.21, Annex 2 – Pleasure Flying
Chap.21, Annex 3 – RFFS at Temporary Landing Sites
(available to download from caa publications website)
PM me if you like.