I've gotta say, if I was a third party to the exchange that involved your suggested message I would think the senior developer was a pompous and condescending ass. In the UK we (or at least I) wouldn't consider what you wrote to be a polite response.
Funnily enough, my last team worked with a software supplier from the UK, and I’m 99.99% sure the above text was copy-pasted from an email reply to one of my overzealous team members. We thought it was over the top, but chalked it down to British culture
