Needed a couple of new padlocks - one for the allotment shed and other for the garden shed - something a bit more robust, a 50 mm padlock. Look at the price difference: Toolstation - 3.52 GBP each: B&Q - 9.72 GBP each: Toolstation - always a port of call if you're after something diyey.
I've found some really good prices for ironmongery/hardware items at Toolstation. But for padlocks I check out the cheapest prices for packs of 3 (or 4 or more) all on the same key, and supplied with numerous keys, so every shed, chained up wheelbarrow, gate, etc. only requires one key on my keyring, and if one padlock fails I have a spare. (I have several sheds at my plot and several more at home).
I was about to post exactly that. I have a box of padlocks from a locksmith. They weren't cheap but they are all keyed alike. He had lots of boxes with the same key but hes 12 miles away so chances of others having the same lock near me are slim. I did the same with the house once I saw how easy it is to break in with cheap locks. All four locks were changed for high quality locks with the same key.
All our external doors have identically keyed 5 lever locks plus indentically keyed cylinder locks. The cylinder locks are just to provide some basic security when we have a visitor without locking them inside with a 5 lever lock. When we're away and a neighbour looks after our hens we change gate locks to spares with a different key.