P Bruno have told me that the cost of the parts is: clutch kit £155.35; flywheel £214.05; set of discs £73.87; pads £39.78, and gearbox oil £4.75. Added together with 7 hour's labour and VAT it comes to £923.22.
Mr Clutch have told me that a clutch kit is £299.99 including labour and VAT; that it's very unlikely the flywheel actually needs replacing (as it's not a DMF) but that if it has surface imperfections then they can skim it for £50 (I've seen at least one web site that says this should be a standard practice anyway when replacing a clutch), and that the clutch and brakes together (but not flywheel skim) come to £450.92.
So that's a saving of £900 off the original price, and Mr Clutch is coincidentally located on my bike route (and bus route) into work.