The repeat pics needed to be done while I was away from home which was a hassle. Then I realised they might need recounter-signing. Passport office gave me the WRONG number in their letters, which was fun on relay telephony, then confirmed I did need countersignatory again even though the letter did not say this at all... Then I had to unfaff and contact my original countersignatory to do it cos it was less hassle than a new countersignatory...
But it's done now, hopefully for a decade if I can find a way of carrying my passport without it being so losable as the last one...