A few years ago I was trundling along from Swansea to Popham
Cardiff Tower - G-xxxx pass your message
Moi - CDF Tower G-xxxx Piper Cub enroute Swansea to Popham at 2,000 ft on QNH 999 Currently North abeam you, transiting to the East of your zone.
Cardiff Tower - G-xxxx, F-27 traffic leaving Cardiff ahead of you climbing to FL 20 or whatever level. Can you route behind?
Moi - I'm in a Cub Cardiff...........