I also found this quite randomly here:
Reference: WO 169/1700
Description: 2 Scots Guards
Date: 1941 Jan.-Dec.
And among the posts of the year, in June was this:
Battalion warned verbally to move to DABA. 2SG Move Order at APPENDIX G
2nd Battalion SCOTS GUARDS Move Order No. 10 issued.
Lifting transport from 13 Res M.T. Company reported to the Battalion at 1330 hours.
Battalion moved at 1430 hours – going by Companies at 20 minute intervals.
Major COGHILL and one N.C.O. per Company had preceded the Battalion and had recced Company areas which are on either side of the L.O.B. Detachment Camp…
The Battalion has been warned that it is to be converted together with 3rd Battalion COLDSTREAM GUARDS into a Motor Battalion
M.T. [motor transport?] Refresher Course for men, who have experience, began under Captain M.N. ROMBER.
Carrier Course under Captain R.A.H. RIVERS-BULKELEY also started.
3rd Battalion COLDSTREAM GUARDS arrived in position two miles West.
M.T. Course for fifteen men with no experience from each Rifle company began.
So it appears that the initial training that was important was with the Bren carriers, probably both to operate them and use them tactically.