Ive seen the lump hammer scenario in use, but no screwdriver, anyone with experience of doing this will know the platters shatter like glass when thumped correctly. Success can be detected by tipping said drive from side to side, and listening for a noise not unlike sand pouring around inside...
There is also some nice boyo's in welsh wales running a furnace called "Secure destruction", that send you nice red heavy duty bin sized bags, and for a set fee per sack, guarantee said bags are tipped into their blast furnace furnace under protective guard. Any magnetic media, used tape drives with buffer chips and anything else that can retain a magnetic memory of the data can be dropped into the red bags and get sent off for gov assured destruction. Its how some very sensitive equipment is sanitized.
There will be someone at the council who has clearance for looking at "restrictive" marked documentation. Or one would hope they have someone. I believe being sc and needing to know is the requirements for this, although restrictively marked documentation can be made available to a none sc cleared individual to read on a need to know basis, provided they cannot take said documents away with them.
Its just sloppy as they have the tools, and there is british doc's available to them via channels I am not at liberty to discuss, poor IT, endless quango's and the computer decisions being steered by someone who had a spectrum once when they were a spotty oik but is in favor with the councilors. Councils are always the lowest of the low on the talent ladder, because anyone with any real knowledge is off being a grabbing contractor for a proper company ;)
- A grabbing contractor ;)