Spoked wheel straightening

[Rtrak]

The back wheel on my 1998 Montesa trials bike is badly out of true. The spokes are made in two halves with a 'turnbuckle' (with l/H & R/H threads)in the middle allowing adjustment or replacement without removing the tyre (the outer end of the spoke hooks into a flange). Has anyone out there had any success straightening wire wheels & if so could they point me in the right direction? Alternatively does anyone know a wheel builder / straightener in Cheshire?