I would check with the MCA.
The new rules (harmonised) are for small vessels in commercial use for sport and pleasure. The word Charter is important in this instance.
Also the Vessel has various definitions as i remember , if you read this section (about page 24/25) of MGN 280
If you own the vessel it will be on a free voyage - providing its your family then it needs no coding - not a surprise as this is what most boater do, however further on it talks about ownership of the vessel (clubs).
In your case you own the vessel but want to help a club, which crosses the boundaries
I would say you have to code in this instance. The best option is to get the club to insure your boat for safety cover, you will still have to ensure you have the correct gear and are trained.
Hope this helps
Boatless - better get down the pub and drown my sorrows