Directives are a wonderful thing!! The reality is that you can still put a DVM on any supply in the 4 corners of the UK and get anywhere between 400 and 440V(ish) - but, if it keeps the Eurocrats happy then we'll call it 'Harmonised'
In the real spirit of harmonisation nothing has changed but the nameplate. When the standard was set at 400V the old margins were also changed so that 415V systems in the UK are now at the top of the acceptable range and 380V systems in continental Europe are at the lower end of the range. The standard may be 400V but nobody actually uses a 400V system. Isn't politics wonderful.