Tumble Dryer in the same cupboard as boiler

Hi,
We’ve been renovating our house, and have recently had a new boiler installed. It was in a cupboard, and with our house having quite high ceilings, we moved it higher up so that we could fit something underneath and make most use of the space. We were advised against a washing machine, as the bathroom (which has the boiler cupboard in it) is on the first floor – so noise, leaks etc – but then when I mentioned a tumble dryer, no objections were raised.

First hiccup: the old hole in the wall was left for us to install a vented tumble dryer. This is now a good metre etc off the floor, and I think we’ll have a condensing problem as the vent pipe will have to go upwards from essentially off the floor. First question, would this, in practise not work?

If not, we have to go for a condensing type of boiler instead. So second problem is that the cupboard isn’t the biggest. There is loads of space above, but there are the pipes for the boiler at the back and once we’ve nudged the tumble dryer through the door (which is a bit tight) should have about 2/3cm on either side to play with. (We’re going to stick in on wheels for easy access to the boiler pipes behind). We are also contemplating putting a vent over the existing hole that was intended for the tumble dryer to encourage circulation, and keeping the door open when in use. For a heat pump tumble dryer, would this be okay?

However, the big problem is, after doing all this planning, I’ve discover that it’s not advised to put a tumble dryer underneath/in the same cupboard as a boiler. Are there any regulations against this? If we go with a heat pump tumble dryers are less of a fire risk. Would putting a fire-resistant/proof shelf above it help with this? I’d love to hear some real-world advice on this, people who’ve got appliance set ups like this, etc. There is no where else in the house that it can go, so would appreciate thoughts and expert advice?.

Thanks,
Rebecca