Whois verifications

[DomainMagnate]

Nominet keep asking me to provide some extra verifications for address, company, contact name etc. They are really persistent too, want some local bills and id copy, which seems quite intrusive.
I'm not UK based, but have a few .co.uk domains.

Is that common, does everyone have to provide some proofs? It's weird since I've held some .uk names for many years and this is the first time.