It is quite simple to fit the Electric seats as most of the loom is in place,the heated seats will also be electricaly adjusted seats as well, the heated seat switches are in the same panel as the electric windows, However you will need some one with Diagnostic kit as the electric seats need...

As Paul says It is worth checking for a Difflock, many owners retro fitted them . Its such a common offroading mod that the kits to do the conversion are now as rare as hens teeth. You would not know its fitted unless they fitted a new knob as well.

On the D2 if the brake light fuse blows the Difflock light illuminates. So check your brake lights are working, this wouldnt normaly illuminate the abs,tc lights though!