Firstly, what does your Permit say? Does it allow Aerial Work or is it prohibited?
There is an AIC relating to Tests and Instruction in aircraft maintained to private standards
http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4W133.PDF but that excludes Permit aircraft.
If you fly with a friend who is an instructor and no payments are made then I can see no reason why its not possible, but if you pay, then its aerial work and subject to the provisions in the permit.