Sticking edge of MDF board to a tiled wall

[ZACCCC]

Can anyone advise on the best stuff to use to stick the edge of an MDF off-cut to tiles?

I've got a bit of a mess of pipes running behind the toilet so I've covered them up by boxing them in using some off-cuts from old MDF kitchen units. I've got the boxing all done but it leans slightly towards the toilet from the tiled wall behind the toilet, leaving a gap of about 7mm between the wall and the edge of the MDF unit that is the 'top' of the boxing. I want to stick this MDF edge to the tiled wall.

 

[Deleted member 174758]

I tend to fix 2 x 1 or 1 x 1 cleats (battens) to the wall and fix the boxing to that. Glue it to the wall and it's bound to get knocked and come away in the future, especially on tiles

 

[ZACCCC]

Thanks for that advice. Not sure I can do it now as the boxing is in place but thanks anyway.