Removed the emissions stuff. Removed the water feed to plenum area. Removed the plenum for the air at the back of the manifold. Got some silicon hose for the air feed to the brake cylinder. Whilst at it I got the hole for the BOV cut off and aluminium welded up. Sounds like a hassle but it wasn't technically difficult. After it meant I could whizz the manifold off in about 10 minutes so it was always an easy first step to check anything out at the back of the engine.