We did a church in a local village a few months ago. I poled it inside and out, the result wasn't great because the leads leaked like sieves, so as I did the outs, the ins got runs down them, then I did the ins and the outs got runs down them.
They still came up looking a lot better than before I started, but the best part was it was the local squire who asked us to do the job. I told him the problem with the water running down the inside, and he volunteered to follow me round mopping up as I went. I bet there's not many window cleaners have had a knight of the realm working as their labourer