Pleasant surprise

I just a pleasant surprise through from the DVLA, I taxed my 1972 Spitfire last month at the post office. But as I could not change the taxation class there I had to pay the £60.50 to get a tax disc, and then get myself off the DVLA local office to change the taxation class and reclaim the tax.
To my astonishment I had a letter in the post today from the DVLA telling me I had paid too much for the tax, offering me a new tax disc and to pay me back for the tax. Makes a nice change when you get a cheque from the DVLA and a greater surprise when they offer it to you without asking.