Further to the discussion about marriages at home/synagogue, I just found the following on a government website - apologies if others already know about this but it was news to me:
Changes from 4 May 2021
Marriages will no longer be registered in a paper marriage register. The details of the marriage will be captured on a marriage schedule or marriage document which will be registered on the electronic marriage register at the local register office after the ceremony.
Each party to the marriage will be able to record the details of up to 4 parents on the marriage schedule or marriage document (for example, mothers, fathers or step parents).
Marriage certificates can only be issued by the register office or General Register Office (GRO). Authorised persons, members of the clergy or secretaries for synagogues will not be able to issue marriage certificates after 4 May 2021.