Instructions:Just placed an ad on Autotrader (which incidentally, you can get 25% cashback on at topcashback, Quidco etc!) and got the following link sent to me with various discounts at Nationwide Autocentres. Link to the full list in next post.
Other similar discount vouchers have been posted here in the past, but the most recent I can find is a couple of months ago and doesn't have as many offers on it.
Comments from previous similar deals are that Nationwide are likely to try and get you to pay for additional work, but if you just need a simple MOT or service then these could save you a few quid.
I think cashback is also available on Nationwide bookings when you use these.