This is a great rig and well known as being suitable for radio astronomy (and a great receiver generally). I have one that I bought many years ago for $700 - so Gav's is a great price. They seem to hold their value too and don't come up too often (actually I'm surprised it hasn't been snapped up already).
Here's a tutorial on the simple 'AGC-off' mod that improved it further for RA -
http://www.thornett.net/Rosliston_Ar...sed_180811.pdf
Cheers, Doug