Hi Jim, the range was abandoned for years following WW2 and came back into use by my local club in the late 1960's.
My Father-in-law organised Home Office approval at the time and the way the system works, providing it remains in use, or no complaints are recorded, it just carries on without inspection.
It's up to the range occupies to keep it safe.
Even today, it's only occasionally used, so not 'masses' of lead.