Removed all drain plugs, cleared out all teflon tape bits with tweezers and bits of wire, and check for bits with borescope camera.
Refitted drains with Loxfal 58.11 thread sealant.
After cure re-pressurised. After 2 hours see a 2cm drop, and start testing. Test all aluminimium lines and their entries, fuel cap sites, port R57 bulkhead and fuel drains, before I realise this may just be temperature/local pressure again, so stop. Test fuel drains from time to time with a fuel sampler, to ensure I haven't bunged them up with the sealant, and reset to reference line at the end of the day.