The headlamp unit is common to many vehicles, there are plenty on eBay in the UK. The lamp itself is also a standard item, look for a Land Rover or mini 7” headlamp without sidelight. Just replace the bulb with a 24v one.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F273228519891