Hi Katie,
For a prior approval application under Part 1 Class A (i.e. a larger home extension) there is currently no fee, and from 01/10/2013 onwards there will still be no fee.
For a prior approval application under Part 3 (i.e. a change of use) there is currently no fee, and from 01/10/2013 onwards there will be a fee of £80.
For reference, the latter is being introduced by the following part of the new Statutory Instrument 2013 No. 2153:
http://www.legislation.gov.uk/uksi/2013/2153/regulation/6/made
Please also note that the new legislation includes the exception that the above £80 fee will not be payable where the same applicant on the same day makes an application for planning permission (for which a fee is payable) on the same site
Thanks,
Steve
