Shed (or general workshop) Security Tips
Window Security
Windows are a weak spot in any shed. Small panes of glass are easier to break quietly than larger ones. Your standard British shed comes usually with 3mm or even 2mm agricultural glass. Where possible modify the window casements and replace two small panes with a larger piece of frosted 4mm glass, or better still with polycarbonate if you can get hold of it cheaply. You can screw a piece or polycarbonate or perspex over the outside of the existing glass panes with thief-proof (one-way) screws. If you want to retain the glass and outward appearance of the window, especially in a brand new shed, screw a piece of perspex or similar to the inside of the frame. This will insulate and help prevent break-ins.Pay attention to window hinge fittings as below, or fix short lengths of chains between the wall and the opening window where the hinges are situated so that removal of the hinges does not release the window itself. Fit commercial window locks, or even screw windows shut if you don't use them for ventilation. The trick is to avoid them being jemmied open.
Hinges
It matters not how many locks you have down one side of the door if you have screwed-on hinges down the other side. They can be removed in 5 minutes and the door or window opened on the hinge side! Ensure that at least one hole on both sides of all the hinges has the screws taken out and replaced with 5mm bolts and nuts. These can't be removed from outside.Locks
Your shed probably comes with a single bolt that can have a padlock fitted to it. Often these are simply screwed on and can be removed just as easily with a screwdriver! Get locks that cannot be removed easily. That means hasps should have all screws covered when locked, or that use bolts and Nyloc nuts. Alternatively fit two rim deadlocks so that the only visible sign is two small keyholes. Even card-proof cylinder ("Yale") locks can be used with a little ingenuity.Internal Storage
Spend time putting additional locks inside the shed, on drawers and cupboards that contain your nicest and favoutite tools. Anything to delay the burglar will reduce the haul, especially if you use an.....Alarm
It's possible to purchase shed or caravan alarms for a few pounds. These will deter all but the thickest-skinned burglar from spending time unlocking the internal storage whilst the noise is blasting away. Fit magnetic sensors to door and windows.Flashing LEDs running from a small transformer also advertise the presence of an alarm and may deter the attempt.
A cheap PIR operated light inside a shed or workshop is also a bit of a surprise on top of the alarm sounding.
WARNING. Any device designed to injure a burglar in the United Kingdom will result in YOU being prosecuted!