Replacing an Old Central Heating Timer

[countrykid]

My elderley parents central heating sytsem dates back to the late 1970's. It's a Baxi Bermuda W2 Fire/Back Boiler. It has been regularly serviced and stilll works ok - but the actual Central Heater timer is faulty. It is a Switchmaster 400. It has a dial style timer knob, where you pull out lugs to set the on/off times, and two switches, one for Timed/Constant, and one for Water/Heating & Water.
In a nutshell, the dial no longer works - it does not go round, hence the central heating/water is either on or off using the constant option. There is no room thermostat fitted (wish there was), and no way of setting how hot the hot water temperature reaches.
Is it possible to replace this very old Timer, keeping the original fire/boiler, and if so can you suggest any suitable ones. I appreciate that this may not be a DIY job, so I would happily call in a plumber/heating contractor, but would line an idea of what is possible, and ideally how much it might cost. Many thanks

[craft1948]

My plumber replaced mine a couple of years ago with a digital clock one..........can't remember how much it cost but it wasn't a huge job. (My plumber loves the old Baxi Bermudas)

[countrykid]

Thanks craft.

[GRUMPY]

Yes this can be replaced with a digital timer,available of ebay or from electrical outlet like CEF etc if you are ok with basic electrics you can fit this yoursel,f otherwise get a qualified electrician,i hope this helps

[heathfield]

Have a look on eBay for 'switchmaster 400'. Several are listed.