Placid As TB says, the ones at Planet X are cheap and look OK. With regard to head shape, the best advice is to try on but we're in difficult times. Giro helmets just don't sit right, on my bonce, as don't Specialized. At the moment I have three lids - one MTB and two road - all of 'em are MET who often do an extra large version of some of their helmets. I also "get on" with Bell and Cannondale ones.
Try START Cycles, as they have some good online deals.
NB - measure your noggin and check the sizing.
