Don't forget that there is about £2.20 of tax on a bottle of wine.
I tend to see what "bargains" there are, always red.
Do make my own fruit wine, although I'm some way off being self-sufficient.
Many of the BOGOF wines in the supermarket are well known in the trade as being correctly priced at the lower price point, but deliberately sold temporarily at the hight point. Hardy's Crest it the most infamous.
Best deals are the Waitrose and Sainsbugs 25% off all wines offers. I got a case of Musar 2005@ £20 less 25% less 5% case discount 1% cash back for using a JL card.