| Hi Mark,
When you say "Wonky" & "it has started flicking left to right" , do you mean the needle itself or that the round guage casing is rotating???
If it's the casing you may be able to get to it by removing the nosecase and if the looseness is not obvious, then use clear silicone sealer on the back etc to hold it in place.
If it's the needle itself that's playing up I have no idea and would rather leave it to the real techies. | 
Guido
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