If you're not planning to do much walking I'd suggest getting road shoes. R540's or 550's are good, inexpensive ones. If you like to match them up with your groupset then go with the 5800's. You can probably get them online from one of the UK retailers for under $100. You could order a pair of shoes at the same time. You'll save a bit of money ordering on line anyway.

Nothing wrong with MTB shoes on a road bike. I have it on my commuter. It makes for walking around the grocery store that much easier.