Hi Jo,
They have a recipe for what they call ‘Family ‘Beena’ in the River Cottage Preserves Handbook, by Pam Corbin…it uses 2 kilo of fruit but I’m sure it could be adapted to whatever amount you have. Hope I don’t get shot for putting it on here lol!
Ingredients:
2kg fruit
Granulated Sugar
Makes about 1.5 Litres
Method:
Place your chosen prepared fruit in a large saucepan. For each 1kg blackcurrants, apples or hard fruit, add 600ml water; for each 1kg plums or stone fruit, add 300ml water; for each 1kg soft berries or rhubarb, add 100ml water. Bring slowly to the boil, crushing the fruit with a wooden spoon or masher, and cook gently until the fruit is soft and the juices flowing. This will take anything up to 45 minutes depending on the type of fruit. Remove from heat.
Scald a jelly bag or fine tea towel and suspend over a large bowl. Tip the fruit into it and leave to drip overnight.
Measure the resulting juice and pour into a clean pan. For every 1 litre of juice, add 700g sugar (or to taste). Heat the mixture gently to dissolve the sugar, then remove from the heat. Pour immediately into warm, sterilised bottles, leaving a 1cm gap at the top. Seal with a screw-top or cork. Stored in a cool place this should last for several months.
Happy preserving! I’m trying the lemon squash recipe this weekend, I’d definately recommend the book, there are tons of easy to follow recipes in here 
xx