Some great news on the Planning front - Prior Notification has been extended to 30th May 2019 (otherwise known as 'Notification of a proposed larger home extension'). This means that householders will be able to build larger single-storey rear extensions under Permitted Development.
For most homes the size limit will double from 4 metres to 8 metres for detached houses, and from 3m to 6m for most other types of house.
Bliss Interiors would be glad to design the extension and undertake the necessary notification to the relevant Planning Authority on your behalf. A client of ours has benefited from an 8m single storey rear extension which has dramatically improved the living space and flow of the ground floor of their home - see drawing below.