Serves 12m homes, so about £60 each home, except also 300,000 businesses, some of which would be quite large I imagine (could be wrong) so probably quite a bit less than £60 each.
Obviously I'd rather have that cash in my own pocket but is it unreasonable compared to profits made by the other things we spend money on, supermarkets, internet and media supply, holidays or car dealers? Not sure, but I'm not scandalised by it either.
For the record I would not have privatised, and if I had done I would have invested the proceeds in infrastructure and improving public services, and not spunked them on tax cuts as Thatcher did, even though I gained from them, but I suppose that was a long time ago now.