Hanimex La Rondette 800S slide projector

[Barleymow]

I'm trying to renovate my wife's father's (1960s?) Hanimex slide projector, so I can show her the many photo slides taken by him, of her now long deceased family & siblings, from when she was a child, 50-60 years ago (plus ones we took in our 20s, 40+ years ago. The projector is in generally good condition, and I've determined there are 2 electrical circuits in it: one for the fan; and the other for the lamp. The fan circuit is OK, and works well, running directly from the 24v mains input and by-passing the on/off switch. The lamp is a problem though. The power goes via the on/off switch, which seems to function(I've tested it with a multimeter), to a step-down transformer that delivers about 13 volts, per my multimeter. The cables to the lamp mounting are sound, and 13 volts is again found at the lamp terminals (which I remade from scraps of stainless steel, as the old brass ones were broken). The lamp I've obtained is an 'A1/215 12v 100w FCR' (like a peanut, with 2 wire prongs). After insertion, however, it won't light up. The multimeter suggests it's OK. Have I got the right lamp for this projector, and do my test readings seem OK? Any advice appreciated please. Thank you.