Yes CG Something which you can't see in this cropped version is these men's comparative height... I would say Coldstream Guards. They have to be a Guards regiment or CMP - No one else could've got away with peaks like that ! Coldstreamers. Looks like an A10 (e1?, no Cupola though) Cruiser II. (Doesn't seem fat enough for the A13 type without the 'wedge' sides on the turret. details don't seem to match either.) 1st Armoured Division? Have some nice shots of 'em in German usage. Regenberg says 35 built, 31 lost in France.
The caption says 2nd Amoured Bde (I have all the War Diaries for this Bde.) which is indeed 1 Div but the book contains many weak captions (Soldiers at Dunkirk etc) and some clearly wrong. Regenberg says 35 built, 31 lost in France. Good chance those two chaps never made it home then.
I'm not 100% comfortable, as I can't pin the exact mark. Reasonably happy with an A10 of some sort. Will ask Bod to have a shufti too.