Take a look at this for (slightly out of date) info http://tinyurl.com/d4ewxwq The old Emery Little office at the bottom of Bath Street has just been sold so that might be available. 4 Palmer Street might be suitable. You may get permission for change of use for 5 The Bridge & 7 The Bridge was A3 use so you can use it for A2. 15 Westway was First Choice Travel so that should be A2 & 2a Church Street (old Chantry TV) might get an A2 consent.
Check out the Estate Agents here http://tinyurl.com/d7t4rjm & you might find the planning portal use class guide useful http://tinyurl.com/c2f63bl