DyManic added a post in a topic Beta 13: MoDaCo.SWITCH HTC One support topic
Ok just installed beta 7 via OTA (from 6).
Have done a switch and setup my email accounts again (via googles default non gmail client and the HTC mail app).
Can report that the email accounts now stick between switches :D
Well done Paul ;)
Edit: Just a thought, is it possible to get the google client shared onto the sense ROM? Have a slight issue with shortcuts for mail - have to make 2 but only 1 works from each rom.