Welcome to pprune, Flyboy!
It also sounds a little like a welcome to the world of aviation is in order too.
While your proposed route might sound sensible, ask yourself why not too many people have done it?
A GtE says, there are big paperwork issues: although, as he says, I have known someone do it with a Eurostar and I suppose one could do it with the C42 and perhaps the Pioneer.
But these are expensive microlights, so won't save you money, and need a lot of cash up front.
Indeed, you will often find the "light aircraft" version of a "microlight" will be cheaper to buy.
While there are things like Taylor Monoplanes, which are light aircraft and so would answer your brief, you could buy a Zenair 601 light aircraft for something that will hold its value and sell later and you can take a pal up with you.
But think also of the value of those "hours": 500 hours in some quirky types will not be much use in the airline world! Haven't all the rules/requirements of CPL hours all changed over the past years anyway.
If you haven't done it yet, check out the
Air Pilots - The Honourable Company of Air Pilots section for potential commercial pilots.