Many thanks guys for this Information.
@ Regorian, yes, that was the publication which I have here at home as well - but thanks anyway
@ maxD - wicked, thats exacly what I was looking for. Volume 2 of "The origin and history of the First or Grenadier Guards" covers the years I am interested in. I have downloaded the book and printed-off the relevant pages - very interesting. I now know basically what he did whilst in London.
I also now have the book "British Minor Expiditions" and the St Malmo chapters are full of good stuff.
With respect to the Muster Books I have printed-off a list of those which interest me and will be visiting the National Archives in March. Thanks for them.
@ km1971 - you obviously know quite a bit about these Muster Books and I am very gratefull to you for providing me with the best way forward. When I am in Kew in March I shall start with "WO 12/1538 Dec 1740 - 1741 1st Foot Guards (or Grenadiers)" and work my way up from there. Many thanks also for warning me of the possible minimum content and what to expect
I know from his marriage record from 1751 stating he was in the 1st Regiment of Foot Guards and from a Chelsea Pensioners Hospital record from 1769 stating that he was 45 years old, had 23 years of Service but unfortunately I cannot decypher his Regiment nor where he was Born (see attachment).
Barnes is my 5th great grandfather.
I did post it on the Rootschat Old Handwriting site, and there were a number of good suggestions for the "Born near" but no breakthrough yet.
Thanks a lot again guys, facinating information.