what was it?

door trimmer?

Several tools that will do this. An oscillating multitool like the Fein multimaster will do it (though not ideally), as will some biscuit joiners (mine says it will in the manual - haven't tried it though). But there's also some handheld circular saws designed to do this as an extra function - Maffell do them.

I've done this sucessfully several times with a Fein Multimaster.

A circular saw and a batten works well if you're prepared to spend 5 minutes taking the door off. No point spending a load of money on a dedicated tool. How many doors is one likely to need to trim?

I looked at getting one, trimming doors is a regular job - I love carpet fitters :-)

Piggin expensive! I use a sawboard & a circ saw as you suggest.

Thanks for all the suggestions. Once I had seen the reply from Vass I recognised the device. Also once I had seen the price I took the advice to remove said door and put the circular saw to work.

Thanks for all replies. Graham

My guess is if you got a man in to tile, it's just for DIY use. And is likely to be very expensive. Unless using it to make a living with. What's the problem with removing a door and using a circular saw?