Just as long as you know it could cause a site to get into all kinds of bother if you were at 60 on air at a managed site, like the NDAC.
From memory I think the place got closed for days while the HSE and Police were trying to sort out last time someone died on a deep air dive there. And every day not trading is a day losing money, which I am sure the NDAC doesn't need.
We've all done it though, but wanted you to be aware of the consequences. Might be easier to do it somewhere which isn't a managed site, like Dorothea or Wastwater, there's loads of decent 50m dives where no-one gets in trouble if it goes to shite
Down in Plymouth there's some good dives at Firestone, Millbay etc in that range, easyish deep air sea dives as long as you get the tide right.
Digs.