Sink Mixer

Got a loose sink mixer on kitchen sink. Any idea's how I can get to it to tighten?
Or do I have to remove the Cooker. If so can anyone advise how to disconnect the gas?
Or is it possible to reach the tap from the outside fridge vent?
Thanks in advance.

The first thing must be to investigate the unit in which the sink is mounted. In the Warwick Due the access is through the back of a drawer. Keith

No Luck there! When I remove the cutlery tray I see the Fuse control unit in the back and solid wooden top that is not removable.
There is no way into the tap from this unit!

Removed the cooker this afternoon, but no good. The tap is in the cabinet next to it with no access from the cooker.
Can anyone advise on how I remove the fridge vent to look behind the sink unit please?
Alternatively I will have to remove the sink top, which also means the fridge will have to come out.
Maybe I'll just leave the blighter alone and hope the tap doesn't fall off or start leaking underneath!!