Just adding my experience of renewing both my BNUCs and CAA PFAW.
Both went very smoothly. The trick is to leave enough time for each to renewed to process. The Euro USC BNUCs renewal involves submitting the flying / pilots log and reviewing and updating the operations manual. This was quite useful as I could streamline several of the operational checklists and the process reminded me of the training I received the year before. Overall I feel the training needs to be further adapted towards DJI Phantom and Inspire pilots because the technology has leapt forward even in the 2 years since I commenced flying. So I had a bit of a to and fro about where the centre of balance of craft is, vital in larger craft with variable payloads but not so relevant with the Inspire with its fixed battery and proprietary camera systems.
The CAA renewal is very straight forward. Takes a while as there are so many of us registered Pilots here in the UK now. 1769 as of the 20th May 2016. That's actually not as many as I had thought there would be so that seems to have slowed down.
All you need to do is fill in the online form SRG1320, pay them £56 and let them see copies of your Operational Manual, BNUCs or equivalent, insurance and Flying logbook. My renewal came back after 4 working weeks. I had phoned them to enquire about the status of my renewal as I was about to commence a large project and they were very helpful.
So I'm now into my second year of commercial UAV operation, I've yet to recoup my original investment of around £7 thousand pounds for the equipment, training and insurance but we have recently been awarded a contract that will run over the next 6 months and will put the UAV side of the business into the black.
Overall I feel more confident now although I still face each flying mission with a level of trepidation, not for my flying abilities, I play it pretty safe, but for equipment malfunction, especially battery failure. And battery / firmware management seems to be at the heart of safe UAV operations.