Toilets+building regulations

[DIY DUNCE]

We plan to partition off part of our utility room and install a WC with sink and extractor fan that works with the lights of the loo. There would be two doors between the WC and the kitchen.
Would you need building regulations approval if you installed a new WC in a room underneath a bathroom and joined on to an existing soil stack?

[thedoctor]

Only if you were altering the drain layout outside or the loo was a considerable way from the downpipe

[DIY DUNCE]

Great thanks for the prompt reply :D