series 3 flasher for series 2?

ive recently bought my 1st landy,a 1970 2a.had probs with the lights and high/low beam stomp switch so decided to give it an overhaul.i wanted to upgrade the the flasher stalk for a series 3 1 and it goes on to the column fine,the prob im having is the shroud that screws on the back of the stering wheel seems to big to cancel the indicators.can you get a smaller 1 or is it a case of a series 3 steering wheel if its different.if thats the case then i shall just move it futher down the column and cancel myself.

any ideas or suggestions hugely appreciated!!!!!!!!
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