Any aftermarket tachometer will fit, though check how it picks up the ignition on the LT side of the coil. Not all tachos pick up the ignition signal the same way, but these days they are pretty much universal.
Another option would be to source an instrument pod from an SX model which has a tachometer included. Looks good too, and keeps the car looking factory standard. Only one wire is required from the LT (low tension) side of the coil and fitted into one of the multi pin plugs connecting to the instruments.
As yours is an '86 model I take it that it is a mk1? I have an '86 45S (Uno mk1) that I put an SX instrument pod into, simply bolts in place of the original though you lose the clock. Then you have to hunt for an SX or turbo roof mounted clock and light unit!
Also, the turbo instruments will also probably fit. I bought one myself but never got round to fitting it. It looks nicer, but half the gauges won't work unless I can find sensors for oil pressure and oil temperature. Was wondering if the turbo boost gauge could be wired to take the place of the econometer!
I'm not sure just how much of the wiring is a direct swap as in the SX instruments, though the turbo instruments themselves will bolt up no problem.
Anyway, hope this helps.