Hi Thunderchild
I doubt that you will unearth a single LOTO prosecution in the UK let alone one with some fine or custodial sentence that will send fear around the Board.
LOTO - Lock Off, Tag Off (or variants) is an American import. UK duties focus on a safe system of work, so far as reasonably practicable.
Sometimes LOTO might be appropriate, often not.
Lots of equipment won't even be designed to facilitate the full LOTO.
As example, buy a domestic washing machine (or many other "white goods"). It goes wrong, so you call out the engineer.
The safe system of work is that the engineer switches off the power at the socket, then pulls out the plug so that the washing machine is isolated.
Then they remove the back of the washing machine before exposing anything that is dangerous if there is a power supply, mostly the electrics.
Unless you have a very special socket you CANNOT lock off the power at that socket and even if you could the engineer could, if minded, simply plug back in to another socket.
If doing the job without any shortcuts, the engineer then makes the repair and puts everything back together before plugging the washing machine back in.
They might decide that they need to power up to check something before replacing the back of the machine and the Electricity at Work Regulations 1989 allow this to happen if necessary and with additional controls - which would include keeping you and those in your household well away from the machine.
So, for your Board meeting if you want some prosecutions you need to search by other words.
If, as example you are concerned about dangerous machines then may be you look at the HSE prosecutions database and search for BREACHES (not the default CASES) where the allegation is of a breach of whichever Regulation in PUWER covers maintenance.
You could look wider and try for breaches of Section 2 of HSWA but you will have huge difficulty in separating out Section 2 prosecutions into those which might align to the relevant parts of Section 2(2) i.e. 2(2)(a) - plant and systems and 2(2)(c) - training etc.
Virtually no point in homing in on cases taken for breach of Section 2(2) as almost all cases are taken via Section 2(1) - matter of HSE policy that Section 2(2) merely provides illustrations of the general duty under Section 2(1).
If you were to scour OSHA and other US safety sites you might find more LOTO cases, but any fines are unlikely to be much of a deterrent for your Board.