There are no extensions to aircraft airworthiness certificates in effect at present. By CofA I presume you mean your annual check (since an EASA CofA doesn't expire). You have a one month/10 hour extension available on that under current regulation. Sadly though the ARC does not comply to the same so that will expire as shown. Speak to your maintenance company and they should be able to work with you on a satisfactory solution once things open up. If your aircraft is based away then can authorise a ferry flight.
At the moment you can operate in England without any problems so long as you're solo or with a member of your household. In the regions engine maintenance/continuing health flights are allowed.
I see you are based in Belgium so the 14 day quarantine is your main problem but I suspect that's not going to last too long.