Rough guide!! note these are my old mk5 clocks!!
The portion of plastic shown has to be removed, plus the top clip that holds the fuel/temp gauges in (there are two screws as well so no probs) you will have to remove the gauges to do it obviously. Be very careful removing them especially the EL connection!! Once out you can chop away!!
you also need a clearance hole as well, roughly here ish!!
measure and mark out front housing remembering that the gauge must sit above the temp/fuel gauge section!!
Just a bit of braveness required gents!!!!