dont you find van mount wfp a pain in the arse for houses as most of my work at the moment is domestic :
It depends on the houses. I'm building up quite a few on my round that would be ideal for a van-mounted system, but a lot of my work would need to be supplemented with a backpack.
I'm also known for being anti-Freedom Trolley, but I'm not really. I just think it's an overpriced, heavy sack truck, but a lot of guys here like them. I only got a bee in my bonnet when I thought they were being miss-sold, to guys who work from cars and still wanted to carry ladders and this stemmed from e-mails from Freedom-Trolley users who weren't happy with it.
But as I say, I'm not really anti-'Freedom'. If you're working from a van, you can use the Freedom as both a 'van-mounted system' and a 'trolley system', so you could have the best of both worlds with it.
I'm sure some of the guys who use it could explain further.
My advice would be to research the Freedom, but also research a van-mounted system, supplemented by a backpack (which would be my preference)
Or, if as you say in your original post, you only want to dip your toe in the WFP world, start with a backpack. You'll get a backpack system for around 600 pounds.
Cleantech would be a good start.
I hope I've been some help.