I’ve recently been granted access to the new registrar feature and the ability to transfer domains to it but almost all the domains I own and use with Cloudflare come up as unsupported.
It appears that both the .co.uk and the .me TLDs aren’t supported at this time. Is there a roadmap or any general plans to support either of these TLDs soon?
Cloudflare cant really say they will support a TLD until a contract is in place, but the plan is always to have every TLD available.
Okay so I’ve just looked on the Nominet site (Registry for .co.uk) and Cloudflare are listed as an accredited registrar, so why can’t I transfer my .co.uk domains 
Because they are accredited, but need to implement the connection. It can a bit to do so. You need to be accredited to even start I would imagine.