Microswitches are usually international standard electrical components. They start at £1.21 and are all less than £2.50 at Maplins. The challenge may be the mounting and what type of actuator button/arm/roller the thing has.
Have a look at the pictures on the Maplin website and see if you recognise it.
This is the most standard one:
Low Cost Standard Microswitches
A low-cost range of
standard microswitches produced to an internationally accepted standard size and operating characteristics. These switches are manufactured from glass-reinforced thermoplastic to give rugged performance. Switches are single-pole double-throw and available in the basic style, or with a choice of actuators attached. Terminals are 6.35mm (&quarter;in.) blade type that can either be soldered or used with push-on connectors (e.g., HF10L). The actuators are of stainless steel and either a 27 5mm long lever, or a 27 5mm long lever carrying a roller.
Specifications:
Contact rating: 12A 250Vac
Body size: 278 x 159 x 103mm
Fixing centres: 222 x 103mm
Fixing hole: 31mm diameter
