[Sixer-h]

Wow - thanks everyone.
OK, I've been on a sharp learning curve on the difference between the various Caps, which I initially found bewildering, but all your advice has been absorbed and I understand the differences now, though why Plessey (and no doubt others) marked the positive end and not the negative end of the polarised Caps is something I'll look out for.
I'll also only change one Cap at a time and check it works before proceeding further, and go for the polyester ones, leaving the big flat silver mica ones alone.

Thanks again

Richard