Any plumbers/central heating boiler expert? Replacing timer

[laplumeofmyaunt]

We have a Worcester combi boiler with a DT20 digital programmer. This allows us to programme 3 on/off periods for the central heating. I don't like it as much as the old manual timers where you could pull/push the little sprockets in to turn the heating on and off. Is it possible to take out the digital timer and replace with one of the older style timers?