The map data is supplied by teleatlas, so it's never Tom Tom's fault! they tell me. The problem with some roads is that although they may of been there 5 years or so, if the road has not been adopted by the local authority it more than likely won't be named or sometimes shown, i.e. the road where I live, from receiving the data, which may already be 2+ years out of date it then takes them a further 4 months to encode it, at least that's what they trell me anyway.
I've just had a lengthy conversation with with them as I threatened legal action against them, see my post above, and they have agreed to supply me the upgrade at a 50% discount.
There is lots of info at this
forum