Just managed to fix mine, here are the details in case it helps...
I have a wireless heating controller, even though the batteries were working they were very low powered. Also I found that my new wireless router was interfering with the wireless on the heating controller. So the steps I took as follows,
1. moved controller nearer the boiler
2. remove batteries from controller
3. turned off power to the boiler at the fuse spur.
4. turned fuse spur back on
5. pressed the reset switch until I saw the light flash red for a second time.
6. put new batteries into the controller
7. Let the boiler finish its start up cycle (approx. 3 minutes)
8. turned heating up on controller and then turned heating on.
9. once it all came on turned heating back down to correct temperature and all was fine.
hope this helps someone
Kevin Nelson, October 2010