In reply to jezb1:
Agree, Vertex vent is... IMHO good for 'elf n safety it has a bit for ear defenders to clip to or a visor etc and a breakaway chin strap, plus very high on head to absorb impact of a falling brick. But too big and high on the head for climbing, caving, mountaineering. I own one but advise against getting them.
I have an old petzl ecrin helmet, but it's coming to 10 years old now and no longer made, not sure a good alternative. They were low profile, hard plastic, doesn't float (if you need to wear underwater)
I thoroughly recommend Petzl meteor. I have one and love it, but it's floaty and fragile (compared to hard plastic) so only for climbing or mountaineering, but perfect for that. Whether it fits OP's head shape would need some try-it-and-see.