Firstly, there is no 'best' graphic design course. It's a bit like asking the internet what the best packet of crisps is.
It depends what you're after. If you don't know what you like, it's worth spending time doing lots of research into the subject and the different types of courses available. Some are experimental, some are more typography based, some are more commercial, some are really pushing the boundaries. Some are huge (200+ students per year), some are tiny. Then it's time to think what/where you can afford in terms of rent/travel etc and whether you'd prefer a small town or a campus or a big city?
LCC has a fantastic pedigree, but has a huge number of students in each yeargroup which does create issues. The best work their students produce is brilliant, but it's the least selective of UAL's GD courses so (imo) the quality soon drops off. If you really want to be in London, it's an option.
Goldsmiths doesn't have a graphic design course, just a general BA Design, some of which could involve graphics.
Edinburgh is great, quite hard to get into.
Loughborough is large course, but very well respected. It has a great record with D&AD wins (if that's important to you). D&AD briefs heavily lean towards advertising/commercially-facing projects which might be your bag, or you might be put off by.
So if you can give us some more info regarding what kind of thing you're after i can suggest lots of good options.