To help try and get as much more life out of these chips as possible I decided to order some heatsinks and fit them to all my working boards (thanks to Winklepicker on J+ for the idea).
As you can see from this bad A01 I took a dremel to the die is quite small (1 cm x 1 cm).
I then went on RS looking for a suitable heatsink, there are 1 cm x 1 cm copper heatsinks on ebay sold for raspberry pi's but they would look a bit silly on a chip this size, they are also very short. It's my understanding that the bigger the better when it comes to heatsinks as they disperse heat better.
So I ended up ordering one of these http://uk.rs-online.com/web/p/heatsinks/7500885/ which covers the majority of the chip without blocking access to the pins (they may need reflowing in future) and is tall but not too tall to hit the B board that plugs in above it.
The sticky backing these heatsinks came with is pretty poor so I removed it and instead used Phobya which is a 2 part thermal compound you mix and it dries like glue. I already had this on hand from fitting heatsinks to ULA (zx spectrum) and SID (c64) chips in the past.
The finished result (yes I need to clean that flux up).
