I’ve had my ride today so I’m a bit less uptight. I do however hate trespass who ever does it whatever they ride.
I love Chilterns riding but it’s not exactly Tunnel Hill/Porridgepot. I do know of bits of single track but you generally have to generate quite a bit of speed to make them ‘technical’. Grims Ditch is great but being elevated and with walkers about I give it a fair bit of respect.
I certainly don’t recognise it as being flat