Sloes and most berries have had a mixed year. It's been an incredible year for hawthorn here (a wee bit north of you), an ok year for elderberries, but for sloes I had to really hunt about to get what I needed (exposed bushes didn't set fruit, and bushes with one side exposed only had fruit on the sheltered side). Blackberries were ok (but it's now about 2 months too late for those) but the quality of blackberry was very poor, I don't think the sugar content is very high this year.
It's not too late for sloes if you can find them.
Curently collecting recipes for The Little Book of Liqueurs..