I can open the boot with the key manually but not with the dash mounted button or the key fob. Have had a look at the solenoid and it isn't seized, but definitely no action when the button is pressed.
Not sure which end to start from.

 

Best bet is just to swap out the boot solenoid out, as this is the similar thing that happened to my girlfriends old mk6 fez.

 

Traced the fault to the dash switch, it had an open circuit permanently. Have ordered a replacement.
Many Thanks