HHH 2019 is now open to enter via the British Cycling online events calendar.
You will first need to register with British Cycling to use the system (quick and free - it doesn't involve taking out BC membership).
This link will take you there:
HHH Entry is £29 (+ £1 British Cycling entry fee) for both Midi and SuperMax routes. Just enter the route you are most likely to complete - we won't hold you to it (though we will be able to tell which way you have gone on the day!).