Is there an easy fix for broken knob on Valliant Ecotec Pro 28?

[plumbingbob]

The bloomin' heating temperature knob has broken (don't ask me how!) and so we can not adjust or turn on the heating
Is there any chance of a replacement and how hard to fit? Its an old model unfortunately

See below

 

[ShaunCorbs]

Common failure you can buy them but need a pro to fit it as it involves removing the case

 

[plumbingbob]

Common failure you can buy them but need a pro to fit it as it involves removing the case

Many thanks for the quick reply.
In the past we have used the Valliant fixed price repair (was £299) but that seems a little expensive for a new knob?
Could it be repaired as part of a service?

 

[ShaunCorbs]

Yes obs plus the cost of said part but 5 mins to fix normally