I have four credit cards which I use semi-regularly to make bigger purchases safer and easier to manage. Usually, at any one time a couple have a balance of 0, and the others have up to maybe £2k spread across them on 0% deals. I move money between them to ensure 0% interest at all times. I always pay well above minimum amount to get things paid off before 0% ends, and with small-medium purchases I clear the balance when the first bill is due, without moving the money around. I've never defaulted on a payment. Adding them all together my available credit would be something like £40k, but I've never gone above £4-5, and almost always it's far less.
Recently, I made a far higher purchase than I normally do - £4k for a holiday. I want to move it from the card I paid on so it can be 0% and all paid off before we go next summer. I notice that my 3 possible cards to move it to all have a 5% fees when I'm sure it's usually 3%. Just did a quick Google and Martin Lewis has offers at 2-3%, including one on one of the cards I have! Why, when surely I'm a reliable bet, am I getting worse offers? I don't really want another card as I already have more than enough for my needs.