Q. mrvibrating - why do you suggest WAMP instead of WLMP?
Because there are one-click installations of WAMP stacks like EasyPHP, XAMPP, SpikeWAMP... There aren't any for WLMP stacks, lighttpd is for people who know what they are doing and have unlimited time due to the lack of a real life. I could get into a load of technical stuff about why lighttpd does not offer any significant advantage over Apache in real-world PHP scenarios anyway, but I am not going to. (It sounds like I have something against lighttpd - I haven't, and it does have some advantages in certain scenarios, but it just isn't for you).
Q. my friend who is a developer keeps trying to persaude me to just install linux and take it from there, but tbh I think I am already facing enough steep learning curves without throwing a totally unfamilar OS into the mix...
No, he is right. Get hold of a Ubuntu Live CD, install it and then get your friend to show you the miracle that is apt-get. Actually, tasksel is the way to go for a LAMP stack on Ubuntu desktop. But I digress, because you really don't want to be doing this either (read on).
Look, if you want to be a web developer you need to spend your time looking at PHP or Ruby or Perl or whatever, not playing around with low-level installations. It's like trying learn how to be a racing car driver by building an engine from a lump of metal. Web developers don't do that, they buy in their hosting services from web hosts.
Which brings me back to...
Q. and can you explain what you mean by "just get a (linux) web host with a one-click WordPress install." ???
Go here, spend £12 for a month on the Advanced plan - get a domain too if you need one, and you will understand.
Good luck, although I have to say that I think you will find it very hard to earn a living as a freelance web developer from a standing start.