Thanks for your interest and information GrenPen.
I was also puzzled about the "missing year" but I guess you've probably got it right as to him or his unit being posted to barracks. Having read one of the links, it suggested that the 2nd Battalion was lacking in discipline and were deployed to the barracks at Berry Head Fort in Torbay for a bit of training. This could somewhat reinforce your theory. Its a pity the document doesn't have more detail as the the dates of the postings, because with so much information on that link and others alike I could probably pinpoint him down to specific engagements.
As to my ancestor being involved with setting fire to the White house. I did find a small article on the incident, but after recent events I think I'll resist the temptation to put too many Google searches out on that subject, after all I don't want the Feds knocking at my door

. Eyes and ears everywhere you know

Thanks again
Stewart