Okay, honestly you could be taking a risk that you'll not pass the MOT emissions test with any HFC's (imho). I'm just telling you that so that you're going into buying the HFC's with your eyes wide open.
I mean I passed the MOT emissions test no problem with my old 03' Zed running Berks HFC's and an Invidia Gemini exhaust system but I have heard of others with the same set up not passing.
I think if you do have HFC's it is imperative that you get them nice and hot before MOT with a good long drive. I did that with mine and never had an issue.
I can't really recommend you anything as I never had any other HFC's except the Berks so that's what my experience was with. Good luck.