There is a guy called James in Lytham who sells Olive wood turning blanks, and he also does training courses on woodturning, his website is www.olivewoodturning.co.uk
Other than that i have tied in with trips to the lakes district to go to A&S Timber near penrith to get some supplies, they do deliver if you order over a certain amount but you dont get the chance to choose which blank looks the best. There website is http://www.toolsandtimber.co.uk/woodtur ... ng-blanks/
There is a guy in Tarleton who puts stuff on ebay every now and again, i have visted his workshop once and he has a barn full of all sorts of timber, which i think he would be keen to sell any of it if it suited someones needs. I can try and dig his number or e-mail address out for you if you like.
If you have found anything else then please let me know as i would be interested aswell.