My previous PEB Stingray was a delight to play, sounded great, but when I took the scratchplate off, there was a badly filled extra pick up route (a la Lakland) that drove me nuts (although it didn't impact the sound). Always worth checking!
God....one of the worst amps I ever owned and I think you are right about the flanger. I thought I had forgotten about it. I seem to remember a completely non functional graphic as well.
I'm not allowed to do 'hard paddington stares' but please could everyone look (or at least think) about whether their suggestions have been done once, twice or even three times before? The fun about this is the original word puns!