The original blade guide assembly did the job but looked a bit ugly so here is Version 2.0 with integrated height adjustment!
Version 1.0
This is Version 2.0, trimmed down it looks much neater.
The main vertical support is a piece of flooring board with a slot for height adjustment, sandwiched between the arm and the backing piece is a right angle metal bracket that is screwed to the underside of the main horizontal arm.
Height adjustment is much easier now, with power on nudge the trigger until the blade is at the top of it’s stroke, then loosen the star knob and adjust the height so the guide rollers are down a bit from the blade tip – tighten the knob.
Alan Mackenzie's Blog 
Hi Alan – how did this idea work with the double rollers as blade guides? gill
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It’s still at Version 2.0 and works well. I find it more useful and more accurate than a jigsaw for internal cuts.
Drill a pilot hole in the workpiece large enough to clear the jigsaw blabe.
Remove the blade guide.
Thread the workpiece through the pilot hole onto the table.
Replace the blade guide and ready to start cutting.
Cheers
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