@ Widebdy.
I too worked as an 'agency pilot' and paid foreign tax broadly equivalent to the rates demanded by HMRC. I always filed a UK tax return.
Some, knowingly underpaid tax. Not me. I have a clear conscience about my time with FR. You evidently do not!
Incidentally, I currently pay full UK tax as a higher rate tax payer.
All the best, Sir.
End of thread creep.