Jack Harry Teesdale laid this down on his screen :
It is not a good idea to have pvc insulation in permanant contact with
central heating hot water pipes. Could you not use clips to secure the coax
away from the pipes?

I have had multiple coax and LAN cables, sharing a duct, unclipped and
no doubt in contact with my heating pipes for the past 40 years. I have
had zero issues and do not expect any.