UEA has responded to the request by the mysterious Mr/Ms Tuppen for Paul Dennis's emails.
The University does not hold any copies of correspondence between Mr. Paul Dennis and Stephen McIntyre, Anthony Watts, Jeff Id (aka. Patrick Condon and Jeff Condon), Steven Mosher, or Thomas W. Fuller for the period 2006 to date.
For FOI geeks like me this is not unexpected. Paul Dennis indicated that he has deleted his local copy of the emails so the only copy will be on a backup server. IIRC someone (perhaps the ICO) has said that if the information is only on a backup server then it is not "held", although whether this is something that would stand up in court is another question. My guess is therefore that there may be more to the university's refusal than meets the eye.