Rates: What they are and are they uptodate, also them check your self by calling the local co. co.. Don't trust a what estate agents tell you.
Also: Management costs for the estate (if any), parking, heating, power, fire cert, alarm, fire alarm, lighting, rights of way, phone lines, internet (ADSL) available, asbestos roof?, insurance requirements, Type of Lease (Repairing/non Repairing etc), Maintance requirements (eg. repainting every 5 years etc etc), guaranties required?, deposit. etc etc.
Times are hard, so how many months will they give you rent free. It would also be worthwhile getting a quote in advance from your solicitor for the paperwork, I think about 1K is the current going rate.