Anne, the picture is not clear enough to be sure about the badges. If someone can make out the letters ASC then I would suggest it is more likely to be ASC.
The term SASC did not come into existence till after the war. I have looked at several ASC photos and it is a definite possibility.
Do you have the original photo?
Can you provide a hi res photo, in focus, of the cap badge and shoulder badge?
Dave
Anne,
In addition to the photo you have told us that Harold was a dispatch rider on a motor bike. If that is true then he would have been in the ASC (Army Service Corps). Not only that, because he was part of Motorised transport, his regimental number would have begun with an M.
There is a Ww1 medal card for Harold Clarke in the ASC with the regimental number M2/192427. ( note that in Ancestry this has been Mis transcribed as M2/1924207).
By studying other people with similar numbers close to this it is possible to interpolate that this Harold enlisted in October/November 1915 and may have travelled to France as late as January 1918. I believe he is the man you are looking for.
With regard to the comment about the SASC (Small Arms School Corps). This small group was originally the School of Musketry and only became known as the Small Arms School in 1919, and it was 1929 before it became known as the SASC.
In your photo Harold is wearing puttees and taped leggings typical of the motorised section of the ASC in Ww1.
For confirmation you need to try to read the letters on the epaulettes (expect ASC or RASC the R is for Royal) and the cap badge
Dave
Hi Im sorry peeps she was getting mixed up with her father & grandfather he was also in the Army all the info was referring to her father no wonder we have brain freeze, grandfather Harold Clarke was in the army but no ideas other than that
Thank You too you all