£50 per wheel isn't expensive.
Much depends on the style and size of wheel, the more intricate, i.e more than 10 spokes, the pricier it is.
I use Spit and Polish, have used them for years, they collect and drop off free of charge too, which is handy.
As for half price (£25) I wouldn't entrust a BBS LM or RX2 split to anyone that charges less than £50 ish. I'm no wheel refurbisher, but I know what's involved in the process.