I'd rather end up in court over kids cutting bars and coming unstuck than getting utterly scuttled by the EA for blocking up a bat roost.
Kid gets into your abandoned mine, injured or dead, you're sued to hell, potentially bankrupt.
Max penalty for destroying a bat roost, £5k fine, potentially 6 months inside. Which means out in 3 months, IF the courts decided to go that far - which is highly unlikely, so a fine of £5k max.
If that's 'utterly scuttled' by the EA then they don't do much scuttling !
If you want to set up a company to limit out liability (a la Roy) then that company still has to do various things to maintain itself, and ensure that it has procedures in place to monitor the safety of non-properly-equipped people or the general (surface wandering) public. All of which costs money and time on an ongoing basis. You have to keep records to show those inspections have been made, you have to pay Companies House to maintain the register.
As opposed to bulldozing or backfilling an adit, which costs a few hundred quid, once. With the possible, maybe, just-might-happed, of the EA coming along and having a hissy fit.
I'll put it this way. If you weren't a mine explorer, and had minimal interest in the hole on your ground, what you you realistically do ?
1. Potentially risk everything in a lawsuit
2. Do a load of paperwork and get it all registered with Companies House (and then have regular paperwork and monitoring/maintenance forever).
3. Fire up the JCB
Madness takes its toll, please carry exact change