There is also a little bit of the show shot inside the flat and I am inclined to believe that the flat used was indeed one inside Broadwood Park due to the various views and angles we can see from the windows as the cops search the place. For example, the first shot below shows Ricky Tomlinson looking out across the very recognisable arch of the awning at Hong Kong Stadium down towards the South China Athletic Stadium just behind it. Broadwood Park actually lines up perfectly for this view.
The second shot shows Coltrane looking at a similar aspect but a little further to the left so you can see the white building (with the red emblem) of the SCAA and if you look closely at the bottom you can see four cylindrical structures that are attached to the aside of the SCAA sports centre.