hi AndyPandy,
I wouldn't be too worried about not having 3 phase. You can get digital inverters to run 3 phase machines nowadays and as a bonus you get electronic speed control which is very good news on spindle moulders.
No more belts to change, plus you can tweak the speed to suit the cutters & timber type to get a really high quality finish.
This also opens the door to buy some very good s/hand machines and more choice of machine.
Toolings not that expensive either, in most cases cheaper than router cutters and you can get or make your own special profiles easily.
Single phase machines are limited by horsepower which in turn limits the cutter block size you can use. 2hp is the absolute minimum imho, the most your likely to get single phase is 4hp, but they come at a higher price, but enabling you to use much bigger blocks.
BTW, 3phase 3hp is more powerful than single phase 3hp.
hope this helps