Tim, mines done the same mate. Hasn't gone through though.
I did change my hose at one point for the dv relocation and then n249 bypass, and have since kept the newer hose anyway.
You actually find that when the car has been driven, the DV is very hot (no suprises there due to its location) - and the hoses get warm too. Mine actually stuck to the inside of the engine cover, as when i removed it i'd hear a noise as it was pulled off, so to speak (no rude comments)
I wouldn't worry unless it wears through - but mine was like it for a good year or so with no
problem. The hose walls are suprisingly thick.