!0W
Reference from the AIP GEN 1.5
5.3.2.2Notified 'Transponder Mandatory Zone' Airspace. For the purposes of ANO 2005 Schedule 5 paragraph 2(3)(b), the following
airspace is notified as a 'Transponder Mandatory Zone' (TMZ):
• The Scottish TMA between 6000 ft ALT and FL 100
• The vertical and lateral bounds of the Stansted TMZ as detailed in AIP AD 2-EGSS.
I forgot about it being 6000ft to FL100
Regards
TUTH