Finally completed the job. Access is a total pain, needed a magnetic pick up tool more than once to get the little torx bolts as I dropped them repeatedly. Couple of issues to note.
1. The bolts are not T20, they're T25.
2. You don't need to remove the high pressure pipe to remove the regulator, you can rotate the regulator to manoeuvre around it.
3. There is a thin metal gasket - don't drop it!
4. Removing the egr valve, the map sensor and a vacuum pipe from next to the regulator improved access but it's still a bugger.
Car works fine now and the removal of the egr and map and subsequent cleaning has improved the running as well.