On those prick tests, and very anecdotal, but my girlfriend works in clinical trials and through her work I've been tested for antibodies twice. Each time, which were about a week apart, I had a prick test as well as lab based test that required giving about 15ml of blood. Both times, the prick test was positive but the lab test (which the company seems to trust much more) came back negative. The prick and intravenous blood were both taken by a profession, so it wasn't just me messing up that led to the inconsistent results!
Add to this that my gf had a pcr test for the virus itself at the start of lockdown that was positive. She was sent home from work and we self isolated for two weeks, completely symptomless. But she has come back negative on every antibody test she's done. I know in some way we are very lucky to have got the testing we're had, but the inconsistent results just left us even more unsure. The whole thing has been an emotional rollercoaster worse than any weather thread.