Sorry for the delay, been off learning to canoe and kayak all week.
the book is The hedgerow hand book by Adele Nozedar, very good too.
similar to your recipe, just fill the bottle ha
f way up with berries and top up with vodka, add up to 200g sugar if you want, I used much less, stand for eight weeks and strain, but like you I will crush them to get all the flavour out.