To get mashed grapes: blend for ~10 seconds in food processor, then strain through a sieve to extract the juice without the seeds.
Place grapes, apple, sugar and lemon juice into a preserving pan or similar.
Using a gentle heat dissolve the sugar slowly, stirring frequently for around 10 mins.
Bring to a rolling boil and cook for a further 15-20 minutes (until it passes the crinkle test).
Pot up in a hot jar and place lid on immediately.
Store in a cool dry place and once opened keep in fridge.
