Where is reset button on old Servowarm Elite 'boiler behind rad' system?

Hi there,

I have a very old Servowarm Elite boiler (one behind the radiator with header tank) where, since the fuse was tripped accidentally, the pilot light does not stay alight. It was working perfectly before the fuse tripped. I believe I only need to press the reset button and the pilot will stay on but I can not find the reset button on this system.

Any help would be gratefully received.

Many thanks