I was waiting for a reply from one of the lads as I've just sold my 600 x 300 x 76 today as it was off tt mk1 and was brilliant and huge.
You need the exact measurement height wise to fit an eBay one to the golf but it can be done. just going to take longer than an expensive one with piping size and routing them. maybe six hours as my tt did. cutting the reinforcement bar which I don't want to do with this golf.
450 x 175 x 65 mm should be a good size. couldn't find anything longer in length with 200 height :(
ebay 310321325903