The wheels i bought have a 110 pcd as opposed to a 114.3 needed for the previa.

Spoke to the vender who advised he will machine them out given that its a .4mm differeance. Also advised that wheels are bought direct from the manufactur like this and are machined by retailers.

Is he talking b*llocks?

It doesn't sound right.
Nobody would design a car and 'modify' wheels to fit !

I'd wait for some more knowledgable answers, but I'd be surprised if this was right. The wheels are the only thing keeping you on the road - they shouldn't need modifying to fit the car !

I agree.. it doesn't sound right... however, it does happen. I have seen countless wheels that have two sets of holes in them for the whel nuts/studs that overlap each other... not multi-fit wheels that have 8/10 holes instead of 4/5 holes.

Personally i think it would weeken the wheel slightly and if it was me i would either look for different wheels or ask another retailer about the same wheels and see if i get the same answer.

a wheel that came with 2 sets of holes i would say are ok, but to open out holes is a no no,there will be slop around the bolts and even with spigot rings you could have problems

Like the others before me, try another dealer. A wheel modified after it was finished it won't function normal, and could deteriorate in time.
I advise you to renounce to that set of wheels.