I am aware that AIA is restricted to 1 allowance of £50k where 2 or more companies are related by group or other control (Sections 51B - 51G CAA 2001). Section 51H also restricts the availability where there are 2 or more related unincorporated businesses.
As far as I can see, there is no restriction where you have say, a partnership business and a Limited company, even though they may be conducting the same or similar businesses and from the same premises. In such circumstances, both entities would appear to be able to claim the full AIA of £50k each.
Can anyone confirm my understanding?