From what I can gather from the 'retailers list' there are none yet within the London area, Scotland, the North East etc, etc. Whatever the reasons, there remains swathes of the UK population unable to physically see before they buy, or simply being tempted to buy by seeing.
It would appear we are in the earliest 'baby steps' phase of retail distribution and that Hornby will have to be dead sure of demand before raising production quantities to support wider trade outlet.