We are trying to fit a washbasin and toilet in a gap between 2 walls that is exactly 1000mm - a semi-insert basin and a toilet with a concealed cistern. The furniture seems to be standard 500mm for the vanity unit and 500mm for the toilet. If the toilet is in the middle of the unit, there will only be a gap of about 70mm between the side edge of the toilet and the side wall. This seems a bit small to me for comfort. Does anyone know if it's OK please?

Code in my area requires at least fifteen inches from center of toilet to wall, sink, etc. So basically, you should have at least 30 inches of clear space for a toilet. Your codes may vary if your not in the states. At this point, if you don't feel comfy with the space, it all comes down to making you happy with the layout. It may mean moving a wall, moving some plumbing, whatever it takes to make the job stand up to your expectations. However, if you are an able bodied person, as long as you have room to sit on the stool and do your business, any room at all on the sides should work just fine.

We have plumbing codes in the USA and I am sure the UK has codes, so you need to check the code on your area. That space is under 40 inches so I am thinking you may need to look fior a very small corner sink mounted kiddy corner from the toilet

You're coming up a tad short of space. Have you considered a toilet sink combination? Check it out at Eco-Friendly, Space-Saving Toilet & Washbasin Combo from Roca | Freshome Let me know what you think. Tom

Maybe even a prison toilet like this Google Image Result for http://www.ballerhouse.com/wp-content/uploads/2008/06/prison-toilets.jpg