75 (Highland) Field Regiment RA(TA) 3 Sep 39 299, 300 (City of Aberdeen) Batteries 3 Sep 39 Jan 40 Jul 40 Feb 43 Apr 43 Jun 43 Jul 43 Aug 43 Aberdeen, UK France UK UK</SPAN> UK N Africa N Africa 51 (Highland) Inf Div 51 Inf Div 31 Inf Bde Group 47 Inf Div Home Forces 1 Army Allied Forces HQ Became 75 Heavy Rgt Locations
75 (Middlesex) Light AA Regiment RA(TA) Locations Feb 41 Feb 41 Jun 43 Jul 43 Sep 43 Sep 44 UK N Africa Sicily Italy Formed from 75 SL Rgt RA Home Forces Middle East Forces 8 Army 8 Army Disbanded
Both are differently equipped. 75 LAA would have Light Anti-Aircraft Guns (for the purpose stated in the name), Field Regiments would be armed with Field Guns (18 Pdr/ 18/25 Pdr or 25 Pdr guns) and used to give fire support and offer bombardments for the forces at hand. So no they are not the same!
In WW2 different types of regt each used the same sort of number sequence, ie regular regts starting at 1, TA at 51 war fomed filling in after that. Hence you can find 1 for RHA, field, medium, heavy, anti-tank, light AA and heavy AA and 51 for field, medium, heavy, anti-tank, light AA and heavy AA. See this page British Artillery Regiments although it doesn't cover AA, it shows 75 field, medium and anti-tank, there was a 75 heavy but they were 75 field changing role but retaining their number.
