In the UK the local council are responsible for building regulations and this is from DirectGov web site...
"The new standards apply only if you decide to change your existing hot-water central-heating boiler or if you decide to change to one of these boilers from another form of heating system."
Found at...
http://www.direct.gov.uk/en/HomeAndCommunity/Planning/BuildingRegulations/DG_10030520
So I would contact the council for clarification...
As for new boilers my understanding is that "combi" boilers only make water on demand so the storage tank and back-up immersion heater in the airing cupboard become redundant but the condensing boilers differ mainly by having a secondary heat exchanger to capture heat from the flue gasses and that these can accommodate a hot water storage tank.
A call to the council planning department may solve it for you. You are, after all, not intending to change your boiler - just to move it.
Peccavi
January 2009