Probably, the way things are going, although it may take many years for the pen-pushers to visit every rural house in the country. :-(
The dumb thing is that I used to have something similar and if I'd left things as they were I could have gone on pumping all my dubious effluent into a stream for many years to come.
Because I thought it best to do the job properly and put in a modern septic tank with a decent soakaway I now run the risk in eleven years or sooner of being told I can't continue with a septic tank because the environment agency now know I have one.
My advice is keep quiet about your sewage arrangements and feign ignorance and surprise if you get a knock on the door :-)
Cheers,
Jeremy