Biennial training flight
 

Is it possible to undertake the biennial training flight to revalidate my SEP rating in any aircraft or must it be done in an aircraft operated by a flying school and kept on a Public Transport CofA?
My SEP rating expires at the end of January and I have met all other requirements except the 1 hour with an instructor. If possible, I would like to do this flight in our clubs 172.

You can do it in any aircraft. The point to remember is that it can be done at any time in the 12 months before expiry and you can revalidate the rating up to 12 months early. Don't wait for the expiry date; if you go over, and the rating has not been signed by an examiner, all the experience you have acquired becomes null and void, you cannot revalidate retrospectively.

There is nothing to stop you doing it on a private category or even permit aeroplane, except that if the instructor is paid there are maintenance limitations(i.e. within 62 days of a licenced engineer LAMS check). This is explained on an AIC.

Don't forget that you can revalidate as soon as you have the 12 hours including the instructor flight in the 2nd year, without losing any validity (i.e. for 2 years from the date of expiry of the previous SEP).

Better to do it early than risk going over and having to do a LPC.