Hey Liam, i urge you not to take the open university course. They are widely discredited by UK based designers and companies alike. They will give you the same if not similar resources as we've given you above, though they'll charge you £185 for the pleasure. They'll then assess you through their own "diploma", which isn't universally recognised (like W3school's is)...
If you want to go the self-taught route then i suggest going through the entirety of the W3schools site, which would give you an amazing grounding in web-development and design. Then spend money getting assessed through W3schools and a local college.
If you'd rather have a tutor - the benefits of which are that you're being taught by someone with experience, the drawbacks being that they can instill bad habbits in your style - then take a look at college courses... What's your background? (age, current qualification level, how much free time you have a week and generally when that is) it's hard to suggest anything solid without knowing what qualifications you have. But if you're of an applying age and have basic qualifications you can apply for a college course in web design/development from the beginning.
I'll warn you now, whichever route you take you will be pushed towards w3schools.com (with varied levels of additional content from tutors or material) so i suggest taking a look through it whenever you can.
Cheers,
Jamey
p.s. if you want to self-teach and need to learn photoshop i suggest lynda.com's video tutorials. They cost, but they have a "photoshop for web design" title which would suite your needs brilliantly. If not then i suggest scrounging up some free tutorials like the ones at tutorialized.com
