Agree Lord B. Bullaces also make excellent gin, and they don't have a thorny problem of picking 'em.
I once made some sloe jam from a load of bushes near the reservoir above Polegate. It was revolting.
Plenty in the Cuckmere Valley, Seaford Head golf-course has a lot.
A bit surprised that they are ready so early, wondering if there is some confusion wth damsons. The latter make better gin and the advantage is you can eat them afterwards, really good in jellies and trifles.
Sloes can be...