T58362 is in a batch of 360 carriers made by Sentinel Wagon contract number T2035 listed as 3" Mortar carriers So i guess she is British
nice one buddy if the plates are missing Nigel Watson may be able to give you more info ie month and year of manufacture etc etc.
once again I am very jealous !!!
looking at the rear axle I am no doubt wrong but it would appear that it is a truck axel rather than a carrier axle (from the lugs on the drive tubes) not that it matters merely something i noticed buddy.