If you want to make sense of all those markings go to the following website.
The Lee-Enfield Rifle
You will find various menu pages regarding markings under:
"Part One - General History",
then also look at; "Buttsocket Markings of the Enfield" and "Basic Enfield Identification and the Facts about Serial Numbers".
There's also piles of other information there as well. IMHO one of the best online recources out there for the Lee Enfield.
As far as the Indian Service rifles, I am no authourity but many were WWII surplus rifles that were bought by India and used in the Military and Police Forces (there are still some in service there today). For example your Long Branch was built in Ontario Canada, then would have seen service in the Canadian Military until (at the latest) the mid-late 50's when they were phased-out and most where sold off.
India did re-serial # a lot of them like the one you have (xxxxxxxxx across the original serial #), they do it this way as they make no secret of the change. Indian Armourers re-fit and exchanged a lot of parts from gun to gun which might be the reason for the new serial # on the reciever. You can also tell when a #-change has been hidden; look on the 'rounded' part of the receiver strap (Buttsocket), there will be a flattened spot where the original # was filed/grinded off and re-stamped over top of the old one, usually with larger #'s.
Enjoy your rifles!
Last edited by DiverDriver; 12-16-2011 at 05:01 PM. Reason: more info
Thank you. Will do.
Expect them to be good shooters too, there have been plenty of reports that they outshoot M1Garands, (and the Garand is no slouch in any department), ie 1.5 MOA, and No4's will do that to 1000 yards with aplomb, due to something in the DNA called positive compensation.