Mick - look at the organisations of the British Army in 44-5. I'd base youe inital force on an Infantry Btn. which would have, at an ammedned 1 base per Platoon -
BTN HQ - CO Use a siganls lorry, and maybe a Carrier,with pipe smoking officer in a great coat. 2 i/c(HQ), 15 cwt. 2 FAO, 1 ALO
Carrier Platoon HQ - 4 bases with Carrier and 1-2 Rifle figures. Use it as Recce
4 Rifle Companies - 3 bases each
Support Company - HQ, 1 platoon, 3" Mtr, with Carrier, MG Platoon with Carrier(actually from Brigade), 2 AT Platoons with 6 pdr and Carrier (strictly Loyd, but can use Universals), Pioneer Platoon, with 15cwt.
12 3 tonners, same model, any type will do.
Tanks -
Churchill Sqdn, use 1 CS and 4 support vehicles, there's considerble debate on which marks to use, but the Mk VII and Mk VIII(CS one) look more like the early ones, so id use those.
Crusiers - suggest the Sherman (I prefer Cromwells as a tank). Get an RHQ - CO/HQ with an Armoured Command Vehicle or Tank clearly noteted, 2 HQ's in Scout cars.
1 -3 Squadrons of 3 Sherman, 1 Firefly (you could use Cromwell instead of Sherman).
Iv'e not costed this(points or cash), but it gives you either a an Infantry Btn from an Infantry division(can use eithr tank, but normally only 1 Sqdn), or Lorried Btn form an Armoured Division, with Shermans only. If it's too much cash wise, start on the infantry, with Churchills.
Hope that helps....
IanS