I use several hosting services for different bits of what I do, and they are all fine. They're small outfits, and I suspect most folks haven't even heard of them.
The potential snag is that your present hosting company might claim that they own your .co.uk registration. It's easy to check - pm me the full domain name if you don't know how to, and I'll look it up for you. I'm sure the others who've replied could do the same.
I know many folks who've got fed up with "large" ISPs lately and moved - I'm now using UKFSN (an Entanet reseller) - not the cheapest, but highly reliable and helpful. Check the performance on adslguide.org.uk or (in my view, more detailed and helpful)
here.