Ford Focus 2007 Zetec Heater Matrix Pipes

[Richiedug]

Can anyone advise how to undo the clips to remove the two heater pipes that connect to the heater matrix under the bonnet as I plan to replace my leaking matrix this weekend.

After a brief look, they appear to be different to the majority of the usual metal sprung clips.

Here is a picture of the pipes (The two black ones on the right )

Any pointers on these pipes or heater matrix removal in general would be great.

Cheers