Broken mixer diverter crank Edwardian Bath/shower mixer

[Johnno]

Hi Gents, My first post and I would like to benefit from all u-s who know.
I have a "modern" Edwardian Bath/shower mixer (tall telephone type) on cranked legs that are on the deck of the bath. The diverter crank in the centre has broke 😡, where the handle anchor screw is threaded.
I can not find anywhere that appears to sell spares that would fit, so I am prepared to replace the whole thing, as although not a plumber, I am a competent DIYer. To remove the cranked legs however would mean me destroying all the decor, as they are on the far centre of the bath, against the outside wall. Can someone advise if replacement taps would have a universal nut and thred? I do not know the make of mine but the leg outlets at the top appears to be around 1.25 inches diameter with the nuts captured on the taps? Or can someone point me to where I may get a replacement (non ceramic) diverter crank?
All advise appreciated - thanks

 

[Puddle]

The spacing between stems is standard,as is the nuts and thread that attach to the taps,it will be 3/4" most common or if posh 1",you just isolate water supplies and undo nuts a top of stems and re fit new ones.
As regards mixer lever,this maybe able to be replaced but make would be required,this often can be found on tap head die on old victorian taps
and when you put new ones on make sure you use change over valve at regular intervals and keep it acive ,as soon stick, if in hard water areas,what happens now is alot on people take only showers,then two years after fitting a visitor wants a bath and you are back to square one,a broken lever

 

[Johnno]

Thanks puddle, I assume the 3/4" is the internal diameter? Thenuts are at least 1 3/8" on outside and are attached to the upper tap body, not the cranked legs. These taps were here when we bought the house two years ago and have never been used, due to the very inadequate flow from both the tap and the attached shower head. As the internal diverter valve moves less than 1/8", I assume that it is filled with corrosion/scale and is the reason I think a replacement tap/mixer body would be justified