From informal contacts with the UK regulator OFCOM, it seems their present attitude is not to panic but to keep a close watching brief on the situation.
The four UK cellular operators are busy building up their 5G networks, but as far as I can see none of them are yet operating in the 3.5 GHz band around e.g. LHR or LGW. This could of course change at any time as they compete to gain value from their licence investments.
OFCOM have also been consulting on possible new uses within the 3800 - 4200 MHz band which is primarily used for satellite services. This of course is immediately adjacent to the air radar band.