Got this from the War Forum !
Just to clarify the several "M"s in the ASC:
M1 : Mechanical Transport Section.
M2 : Electricians
MS : "Mechanical Specials"
MT : Mechanical Transport or Motor Transport.
"T" (T1/T2/T3/T4) were indeed, all Horse transport
From a book in our reference library entitled; 'More sources of World War I Army Ancestry', I can tell you that the Army Service Corps is noted for it's complicated system of letter prefixes to their service numbers. These prefixes indicate the trade of the man. The ASC was split into four branches:
Remount - The department which procured and issued horses for the Army.
Supply - Dealt with all supplies.
Transport - Provided all the Army's transport requirements except those catered for by;-
Mechanical Transport - the motorised branch of the Transport section.
These four branches had the prefixes R, S, T or M respectively.
M/1 and M/2 prefixed men were in the new Army Mechanical Transport as electricians and fitters. M/2 could also be used as drivers.
I hope this information is useful but if you require any further assistance I would suggest that you contact the Army Service Corps (now The Royal Army Service Corps) Regimental Association. Please see their contact details below:
The Controller
The Royal Army Service Corps and Royal Corps of Transport Association
Dettingen House
The Princess Royal Barracks
Deepcut
Camberley
Surrey
GU16 6RW
Tel: 01252 340891
(NB: No Fax, Email or Internet facilities)
The Army Service Corps was honoured with the 'Royal' prefix in 1918 and so many World War One enquiries will relate to the Army Service Corps or ASC. The RASC was retitled Royal Corps of Transport (RCT) in 1965. In 1993 the RCT was amalgamated with others to form The Royal Logistic Corps but it is still appropriate to address RASC and RCT related enquiries to the above address. The Association makes no charge but welcome the provision of a stamped addressed envelope for their reply.
I hope this information is useful to you.
Yours sincerely
These 2 medals are for sale .... just to give you an idea of their price !

M2-021739 PTE G HOUNSLOW A.S.C. £55
M2-098814 PTE AO WEBB A.S.C. £55
http://www.rbjmilitaria.com/index.php?f=data_home&a=1Annie
