I use a very similar grain bill but I do include about 400 gms of crystal. I get a good malt profile using the WLP Irish Or Scottish. Given the FG you have used the right amount of priming but the yeast may have given up. You could add a bit of yeast to each bottle or try it on a couple of bottles and see if this improves it.
Thanks Barry, what I ended up doing was packing all the bottles up in milk creates and puting them out in the sun with a black plastic bag over them for a couple of days. It seamed to finish off the carbonation a bit more, and I guess its not that bad. I have just been drinking a lot of Guiniess of late.