TBH i think they just want to make sure you intend to get the work done safely, i have never met a bad CORGI/GSR inspector, i hope that is down to the way i treat them and the hard work put in making sure what i am doing is acceptable, they always find something to put in their report, who doesnt when they do an audit? but it is always fair and straight forward, if you have CEN1 and it was done recently you must have CPA1 as well, if you are doing work on HE condensing boilers they will be looking for you to have and be able to use a FGA, you can borrow or hire one, you dont need to own one right away, BUT be careful if you borrow or rent because he could ask you "what if you get called to a repair and dont have a FGA, how can you confirm the boiler is safe to leave"? the answer would need to be make safe till you get back with the FGA!!!!! make sure you have all the paperwork you might need, blank caps, meter caps, LDF yellow spool PTFE tape etc etc, all the stuff you need to make everything safe,