Mobile Windscreens Bristol who trade under the name of National Windscreens at Bristol can supply windscreens. The manager there is Mike Ackerman (Mike.Ackerman@mobilewindscreens.co.uk), tel 0117-3042000. They have in stock heated and normal 411 screens. He states that these fit 408/9/10/11. He will supply and pack a screen for you but requires you to sort out the carrier.
The rubber seals are stocked by Bristol Cars Services who say that seals cover 408/9/10/11. Graeme Payne (mob 07787-138079) is the contact there and confirms that all are covered.
The other company who may have everything is American Cars Care Services Ltd, owner Martin Barnes (mob 07769-906525) firstname.lastname@example.org . He has some 408 screens in stock and states that 408/9/10 all have the same screen but the 411 is different.