I like John993's idea of taking it in bits and pieces. Who knows? Maybe you'll hate traveling on a bike? ... it certainly does not suit everyone and it's not all Roses and Rainbows.

Have you traveled outside the UK before? (by any means, not just by bike)
Some have a vision of travel ... then get out there and realize it's pretty hard work.

I'd start with the easy stuff. Over to France, down through Spain, maybe Portugal. Ferry over to Morocco ... spend a week or so exploring around. That's a good intro.

The trick in Europe is living/traveling cheap (not that easy), the trick in Morocco is not getting lost and not getting dead. I'd team up with a rider or two if going into remote places. More fun too with a few mates.

Best to go somewhere beautiful where you speak the language or can pick up a few words to survive. Spanish, French and Erdu will work to start.

Once you start a bike shop you'll be prisoner to it for at least 5 years ... if you can even make a go of it. Not an easy trade. Just ask Touring Ted. You not only have to be a mechanical genius and a Saint ... you have to be a phycologist and divorce counselor as well.

All the best!

PS: I dropped out of Uni at about your age, worked a bit, saved some money and took off ... headed SOUTH into Latin America. Spent the next 7 years traveling ... on but mostly off bikes. Be careful what you wish for.