There is no single list, per se, but there are ways you can research this.
Your use of a GP will be limited to your location - they have catchment areas. In an emergency you can access a walk in centre or a private GP. You can find reviews of surgeries online but I've never seen reviews of particular NHS GPs themselves.
The best way is to decide which specialism you may want. If you aren't ill or need to see a consultant yet you can still research.
One way is to go to the websites of the top private hospitals - King Edward V11, (off Harley St and where the Queen goes), the Lister, Chelsea, and the London Clinic (off Harley st.) What you will find is that many consultants work across several of these - they have practicing rights in more than one usually.
Nearly all these types of hospitals have a search box on their websites where you enter the type of treatment / condition you want help with. It brings up a list of consultants.
Many consultants have their own websites (which are linked to) so you can read about their training and specialisms.
I don't live in London but am close enough to access it and found my own consultant this way after doing a lot of digging online, trying to find the best fit for my needs.