Apologies but don't know Manchester very well other than my lad living there. However, if you're prepared to jump on a train and not travel too far then I know of one place in Bourneville (near Brum) called the Bike Foundry. Their courses are usually cheap and practical. I did a wheel building course there some years ago for about £50. Failing that Cytech do a home bike mechanic course but they're not cheap at around £300. A much cheaper option is to find a bike charity near you (Google may help) and offer to be a volunteer, like I did here in Stafford. They teach you an awful lot, you have a qualified mechanic guiding you and you get to know all the tools and tricks of the trade. Then, of course, there's YouTube 👍