Transfer number plate

Hi,
I want to transfer the number plate on my S class to my Land Rover.

I then will be selling my s class.

I have the form "Application to transfer or retain a vehicle registration number V317" which looks straight forward, so when my Land rover has the new plate from my s class what plate does the s class get ? Is a reg. provided by the dept. at HMGov Swansea ?

Thanks