Smaller steering wheel on IIA???

I went to change the steering wheel on my 1964 Series IIA, only to find that the very tatty original chrome spoked wheel is secured on the splines by a pinch bolt, rather than a big nut on top of the column. All the aftermarket wheels (Mountney etc) I've seen are made for the usual large-nut-on-top-of-the-column set up. Can anyone suggest where I can source an alternative wheel. My existing wheel is 16". I don't want a really small one, 14" or 15" would make a difference. Many thanks. Ed Mason

You will need to buy a steering wheel boss and job's a good un.