Wow, those prices are amazing!
http://www.hfminis.co.uk/shop?category=accessories~plastic-bases
Most of those bases are even a bit lower than my usual discount base supplier, EM4!
http://www.em4miniatures.com/acatalog/MINIAATURES_BASES.html
I've seen a number of Hasslefree miniatures and the bases are going to be the same size as their
GW/
PP equivalents. Just make sure you order the correct width. The standard
GW round is 25mm.
Thanks for the suggestion.
Edit.
Judging from the selection, especially the inclusion of silver 30mm lipped hexes and 25mm lipped squares, I bet they are sourced from EM4 who is also a distributor under the name "Dice & Games Distribution Ltd" . Either way,
HF has the best prices for most of them.