Hi Chris,
Just a though on the cap badges. I think it would be a good idea to do them by Division and/or Brigade.
For example - Guards Armoured could include all 5 Foot Guards Regiments, useable both as infantry and armoured, plus the Household Cavalery, Royal Artillery, Royal Engineers, Royal Corps of Signals etc, etc.
My rational for this is that as a modeller I would mix units from the same Brigade and/or Division but not necessarily different Brigades and Divisions.
Standard Units across the Divisions could be generic to each set ie Artillery, Engineers, Signals, RAOC etc.
I'd be much more inclined to buy a Divisional Set rather than 5 or 6 separate sets to get the divisional badges I wanted.
Alternatively do a set for each Division with the main teeth arms included and a separate set for the support units. Either of these would I think might be more popular and useable and provide scope for the more obscure units, such as Medical and RMP.
Al