Have just done this job in 45 minutes or so. Was fairly easy as long as you followed the video correctly. The locations of the screws are an exact mirror image of the US version.

Its common for the filters that are removed to look absolutely filthy, but apparently they are still fairly efficient even in that state. But I would definately say there is about 10-15 % more air now blowing out of the vents

Thanks for all the advice on here.