Replacing old pipe work

Hi everyone. Hope your having a nice day.

I was wondering if anyone could help with the following ?

The existing hot and cold water pipe that leads to the bathroom on the first floor needs to be covered in the kitchen. I was proposing to do this with a plastic double pipe cover. The problem is there is a tee joint that sticks out as seen in pic 2. Should the whole tee joint and part of the pipework be removed using a reciprocating saw, then join both ends using a pipe plastic ? Is there a type of compression straight coupler to connect a plastic pipe and the old piping ?

I would greatly appreciate anybody s advice in this matter cheers.

Thats old galvanised steel pipe and should be completely removed if possible.
The only reasonable thing to do to the existing pipe is make it the same as one behind (with plug straight into Tee) should probably change for brass plugs, for what its worth....

Thank you very much for the advice. The pipework shown in the picture leads directly to the mains water valve which will also need replacing at some stage in the future.

Best to repipe now as you are doing other work, then make good/box in after.