God that is so similar to mine!
You should get the local hand wash to do it.
I supply my local place with a mit,drying towel and cleaning products (especially for the alloys), just pop them in the boot before hand, the chaps know me now and have no bother doing this. Well that is my solution what I do when I can be bothered doing the runs up and down the stairs, get some funny looks at wash place, but at least you know correct products are been used on it and your wheels wont dissolve over the next year.
I hope you took it out for a blast today and got the roof down. I had some funny looks today driving around with the top down and side windows. Proper commitment that!