Replacing the seals behind the timing case requires disturbing the front portion of the head gaskets, I decided to just go through with a complete clean up of the timing system and take heads are off.
Bore looks good... apart from sucking out any carbon bit's I'm staying well away from that area.
Of most interest was the guide rails, whilst not heavily worn I wouldn't have expected the clips on the upper rails to be split, or any areas that were worn through on the rails.