Volume/squelch Control for Uniden MHS350 Handheld VHF

I have an old Uniden MHS350 h/h VHF which was working perfectly, but the volume knob and the spindle to which it was attached, were loose and could be pulled out. I lent it to a friend who, unfortunately was careless enough to lose the said assembly.
The only way the set can now be switched on and off is by detaching the battery, and there is no way of adjusting the volume, which seems to have been set very low before the part was lost. Does anyone out there have one of these radios which is not working, that I might buy for spares?Alternatively, I would like to know of a company which sells parts like this.