If it is a new house then, yes, it is true, one needs a ramp to one of the principle entrances. It is all part of Part M Building Regs. It does not have to be the front-door - but it must be a door that enables a person in a wheelchair to access the main downstairs rooms in the house. In other words, it can't go into back door to a Utility Room where the person can't then access the other room. The maximum slope on the ramp - unless the house is on a severe natural slope anyway is 1 in 15.
Now I'll let you into a small secret. I built mine in wood - several sections, bolted together, because it is 300mm to my front door - and that's a 4.5m long ramp. My house has just gone through Building Control approval. I was really concerned the BCO would not approve it, because no-one would confirm or deny I could do this beforehand. Hir response was 'Are you keeping that there' - To which I replied - Do I have too. To which the answer was - No. Not sure it will work for every Officer though.
PS Does your friend realise the downstairs loo must be wheelchair accessible too? - it generally means the door must open outwards into the hall.