In reply to mick taylor:
Ive not had success with damsons nor blackberries, elderberry wine is nice but takes a few years to mature, at least 3 but the longer the better.
Elderberries contain a lot of tannin so you have to be careful not to ferment on the pulp too long, perhaps only a day then press the juice out.
Blackberry and elderberry might work together, but make a small batch to test it first. If you make a batch that is just ok, consider making it in to mulled wine for winter (peppercorns, sugar, cloves, cinnamon sticks, orange, juniper berries etc).
Youve got a lot of fruit there man!
If I recall my elderberry recipe for 1 demijohn is 3lb elderberries, 1100g sugar, water, 1 campden tablet, then 0.5tsp potassium sorbet to stabilise once finished. Ive tried various different yeasts but dont really have a preference, the all purpose red is probably as good as any.
Post edited at 15:08