As above. Smash the mani cat out and you can fit a decat pipe in the middle, or fit a facelift mid section which includes a small silencer box.
I'd seriously recommend not decatting as gain would be minimal and usually more hassle than it's worth, especially for MOT time.
If you're set to decat then I'd recommend to facelift midpipe with silencer box just to dull some of the decibels.