Friend of mine has a helmet for sale - unused (daughter fell out with boyfriend before he got his bike!). 

Friend says

 ”It's a MDS make, black with full face visor and never used or dropped”

I asked about size and price - interesting response for the purposes of an advert!

” It doesn't have a size written inside, but it fits me and is about 60 cm inside measurement.”

“It cost £100 new”

Let me know if any interest from anyone who happens to have the same size head as my friend

Tom