I use my Mass all of the time (I got mine new from Spink 3 or 4 years ago and saw a used copy go on eBay for £102 a few weeks ago) and Wren is OK for a quick mint/moneyer/class check, but otherwise it's too basic. I also use Brand's BNJ paper "The Short Cross Coins Of Rhuddlan" whenever I pick up another Rhuddlan.
I'll try to pick up a copy of Short Cross Legends after Xmas - thanks for the recommendation.
I didn't see the Austin, but speaking of Mass, I picked up this example of Mass 704 (Class 2 Sitivene on L) in 2013. Like Mass's example it's on a misshapen flan, but mines shows that his example was missing a distinguishing extra floating stop over the L. Not the best condition, but my only class 2 and nice to be able to add something to a Mass example.