Does it have a temperature control and thermostat ? Ours just had a 40 watt bulb in it and was left on all the time.
the element came from ebay about £7 you just select the wattage and length. they come as straight lengths and you just bend to shape. the thermostat came from RS about £20https://www.ebay.co.uk/itm/STRAIGHT-ROD-TUBULAR-HEATING-ELEMENTS-1000W-240V-20-TO-84/303354054251?hash=item46a14f866b:g:djkAAOSwdeReqFI8 https://uk.rs-online.com/web/p/thermostatic-switches/7334729/
sorry didnt take any as a made it. but its a 150mm x 3mm tube with the element in the bottom a wire mesh over the element that the rods lay on. i welded 30mm bolts on the outside as spacers and fitted it into the box and filled the gap with glass fibre insulation. the thermosat probe is in the top of the tube