Access to kitchen tap on Fiat Ducato Dorset

Hoping someone can advise please.

How in earth do you access the kitchen tap connections on a Fiat Ducato Dorset? 

The mixer tap is situated at the centre back of the sink.  

Underneath the sink is a wide shallow shelf with a drop down door. 

Feeling around right to the back of this there doesn’t seem to be any access to the bottom connections or tails of the tap because there’s a panel that comes up right behind the sink bowl, as far up as the surrounding work surface so you can’t get to the underneath of the tap from here.

Under the drop down door is a small drawer. We pulled it out but the unit it sits in is sealed all round so no access there. 

Even if we lifted the sink out, the panel running up behind it is sited further back under the level of the work surface which seems to be sitting top of it, so I can’t see how we can get at it there. 

Looking from outside the van the kitchen tap is quite some distance along from the fridge vents so I’m not sure that’s the answer either.

Short of drilling a hole from outside to in, through the side panel of the van, (not serious) I’m stumped. 

Help! 

Please and thank you.