Very true that, and at highly inflated prices for a lot of their stuff. Higher prices for the convenience factor, sure that's reasonably acceptable (depending on the difference), but some of it is taking the biscuit.
The most conveniently placed McColls for me, in the opposite direction to where I normally go at that, got taken over by Premier last year. I can't immediately recall if the other one further on is Martins, McColls or whatever now, but I don't use them anyway. I especially avoid the Premier one, as they happily sell energy drinks to children who are clearly too young for such things. With business ethics like that, I'd rather not support such a shop, and from the sounds of other posts it's similar in places like McColls.