On Thu, 25 Feb 2016 14:18:07 +0000, MJC wrote:

We didn't have any special HV AC supplies but stores did have a signal
generator and powerful audio amplifier. I managed to scrounge a large
open-centred coil (meant to generate a magnetic field around a bell-jar)
and a collection of high voltage capacitors, waxed paper in steel cans
with ceramic terminals on top.

I'm guessing you mean like this:

http://www.ebay.co.uk/itm/SIC-SAFCO-...-HIGH-QUALITY-
PAPER-IN-OIL-CAPACITOR-NOS-/151689743255?
hash=item235169cb97:g:N3sAAOSwKrhVXwzP

I still have a couple of dozen of this type here.