In reply to Al Mouat:
I went back to my old Edelrid Ultralight, which unfortunately is anything but.
However, it was, at the time, the only helmet that I could fit onto my 64cm head (I had to faff around with the chin strap since I had to pay out too much of the webbing, but that took a couple of minutes to remove one plastic clamp).
Should have bought a spare Salamander XL, as my problem is not so much head circumference but shape. My skull is rather long from occipital bone to brows, which is, according to a recent paper, associated with certain Neanderthal derived alleles (not joking!)
CB