>Although I'm going off now to do a bit of my own research on the Thinkpad, if anyone has any comments (for or against) the Thinkpad (specifically as regards Linux installation but any comments are welcome) I'd be very grateful.

Actually, the Think Pad is one of the most supported Linux Laptops. Even IBM supports Linux on its newer models.
You'll want to check out:

http://www.linux-laptop.net/

j