Some kits suggest having slightly more than 23 litres because about 5% is lost as sugar is converted to co2 as well as alcohol, and this is lost into the air, reducing the overall volume, and racking inevitably causes further losses, as well as some evaporation.
I did try using tinned gooseberries, but their flavour is very bland compared to fresh ones, so that so many would be required, it would be rather economical. They also contain lots of malic acid, which will need to be corrected with tartaric acid to avoid a slightly medicinal flavour.
Worth considering is using cheap grapes. Tesco now have green seedless grapes at £2 per kilo. This is remarkably cheap and suggests there is a glut of them. A kilo of fresh grapes, crushed, pressed and fermented will yield a bottle of wine from 100% juice. As they are seedless, you can simply run them through a juice extractor without crushing and pressing.