Changing a radiator for a towel rail - horizontal to vertical inlet fitting?

Hi there - I'm trying to swap out a normal radiator with horizontal inlet and outlet feeds for a towel rail that has vertical feeds.

To minimise disruption and reduce work/risk I'd like to keep the current valves on and just put in a junction between them and the new towel rail.

Is there any kit out there that lets this happen without the need of replacing the valve and thereby depressurising the whole system?

Thanks in advance