My fave would have to be a plain toe oxford, in calf - I like the simple style.
In terms of different styles, I do not like black derbys that are not full-brogue and dislike double-monks.
Lobb used to have all three British Royal Warrants; however, they no longer have the Queen's warrant.
You need to find out when Prince Charles gave Lobb his warrant and the shoes would pre-date that, the Royal Warrant website have help...
A tailor may offer a discount for multiple orders after the initial pattern has been made, you pay upfront, etc.
Some tailors offer a discount on additional trousers if purchased with a suit, so some tailors do offer discounts; although...