Browsing in my local Waterstone's this morning and I found a Rev. book entitled "The Rev. Diaries". I wasn't even aware a Rev. book based on the series had been published. It was written in a diary format in the words of Adam Smallbone who is played by Tom Hollander in the series. Didn't look that great so didn't bother buying but other fans may wish to purchase.
It was released on 27th March 2014 so is actually brand new obviously to tie in with the new third series.