1939 TA RA SNCO's Chevrons question

[FMT600]

Hello all,

Can any Royal Artillery expert please assist me in confirming the type of rank chevrons and backing if any a circa mid/late 1930's RA Territorial SNCO (Sgt for the sake of clarity) would wear on the No1 dress/Patrol blue uniform.

I suspect gold Bullion, with RA gun worn above the chevrons (also in gold bullion thread on dark blue), however would the bullion chevrons be set on a red border/backing as on todays RA No1 dress or directly on to a blue background as per earlier practice, again I suspect straight on to dark blue but I would like to be able to confirm this.

Regards,

FMT600