Hello 3 avenues 1) write to :- Certificate Service Section, General Register Office, PO Box 2, Southport, PR8 2JD United Kingdom.
2) email :-
certificate.service@ips.qsi.gov.uk3) telephone 08456037788 opening hours UK time Monday-Friday 8am-8pm & Saturday 9am-4pm.
I use gro.gov.uk (google) then go to Registration Services- Certificate Ordering Service. Click on Order A Certificate On Line Now. You will have to now register, then follow instructions. I ordered a certificate from R.A.F. Wegberb in Germany & did not know half the information required & got a certificate. Best of luck Peter