I got my mat from a model shop, it's basically the same as GW's only cheaper. One mat should be enough to make 4 pitches as well.
All in all I think it will be one of my best boards to date! (and model friendly too, so Lagerbottom need not worry!
)
Spazz
Yep water down that glue and I found (on the second one unfortunatly) that a rolling pin or similar worked well getting all the creases and bumps out.
Will put pictures of my new creation up next month