Hi Nigel
I get together with a variety of musicians some brilliant players others not so, it doesn’t make a difference we all just enjoy playing and all had to start somewhere. Some tunes I can play well, others I manage to pick up half way through or have just managed to pick up when the tune if finishing which is really disappointing as you then want to keep going, I do usually manage to finish on the right note. Have been playing sometimes and thought I was playing the wrong notes only to find later it wasn’t me it was someone else, you know something isn’t right but are not sure what.
Another suggestion is to sit next to a PA player then no one will be able to hear what you are playing. When I started playing I joined a local folk orchestra and was lumped in with the ‘boxes’, my little concertina was surrounded by about six huge accordions I was playing an Anglo at the time and played a whole tune on the wrong row, no one knew as I was drowned out, I do try to keep well away from them now.