I wasn't suggesting that they would take up all of the space, however, for the boxing to be that wide, at least one of the pipes must be toward the far right.
Maybe, but that would seem a little odd, given that all of the pipes (as you go on to say, quite probably 5) p[rsumably go to the boiler (on the left) as well as up and down. Is it possible that the 'boxing has been made about the same with as a kitchen unit, for aesthetic reasons,with the pipes all in the left-hand half of it?
Given that a dry lining box is about 143mm wide, there is a high probability of a pipe being in the way. At a guess, there will be 5 pipes (gas, cold supply, DHW and two central heating pipes).
I would think those are probably 200 x 100 mm tiles, in which case the boxing is about 450 mm wide. Even with a back box 143 mm wide, that would still 'leave' about 300 mm, so I've not sure tht there is a 'high probability' that there wouldn't be a 'space' between pipes of at least 143 mm.
In any event, that 'boxing looks reasonably 'deep'. If a dry lining box were installed 'through the tiles', the tiles + adhesive + board could well amount to something approaching 20mm, making it quite possible that the box would fit 'in front of' the pipes, even if there were pipes in that place.
I guess that the OP could cut out a section above the tiles to work out where the pipes are but that would require him to fill and make good. It strikes me as being a lot of work, especially if there isn't sufficient space. Alternatively, if the OP takes off the plinth, they may be able to see where the pipes running up are.
The pipes are likely to go both up and down, so may be visible 'from above' or behind the drawers/units below the worktop.
Of course, the OP may know where the pipes are. If it were me, I feel sure that I would have taken a photo before I put the 'cover' on the boxing!
Kind Regards, John