Drill bit help please

[Jonny ///M]

Hi there, looking to drill a 40mm hole for a push button flush on the toilet so my dad picked up a 40mm hole saw.

I notice we need something else so purchase http://www.diy.com/nav/fix/power-to...-Holesaw-Arbor-With-Drill-Bit-11-1mm-11407733 to hold the hole saw.

The arbor doesn't fit in the smaller sized head on our drill

I can't see an adapter on the B&Q site so can anyone point me in the right direction please?

 

[Jonny ///M]

It is a wired drill we're using but its a pretty old one as far as I can remember. Can't see that screwfix site for some reason, signal is crap in this hospital.

Its only a wooden panel we're drilling and it won't have tiles over it.


Next question...is it ok to trim a little off the inlet to the cistern? With the 90 degree elbow ifs sitting a little close to the side of the the unit for my liking and the inlet has room to spare.