Welcome to the DIS, Judda.
You've come to the right place for help with your trip. You've got plenty of time to pull together your plans - before you leave, you'll have the answers to questions you didn't even know you had

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Virgin is the only airline which currently flies directly from Manchester to Orlando International Airport (MCO). There are several charter airlines which fly into Orlando Sanford - Excel, First Choice, Monarch, My Travel, Thomas Cook and ThomsonFly. The charters
tend to be cheaper but not as flexible (for example, many only fly on certain days of the week). MCO is closer to the WDW area than Sanford, but both are accessible via quiet toll roads which break you in gently to driving Stateside. If you don't intend to drive, MCO may be the better option as the costs to transfer to your accommodation will be cheaper.
Would you prefer to book a package or to book the elements (travel, accommodation, car hire, etc) separately? DIY may seem daunting for a first trip, but it's actually surprisingly easy - especially with help from people here. Disney hotels
can seem out of reach price-wise, but you don't have to pay the brochure prices unless you want the comfort of a package. Villas can be a very cost-effective option. You'll find that a lot of us here are polorised in our opinions of what makes a good Orlando holiday. For some of us, nothing but a Disney hotel is an option. Others prefer an offsite hotel on International Drive, the US192 or Lake Buena Vista. My personal preference is a private villa, but the options can seem bewildering. Most owners will tell you that their properties are within 10 minutes of WDW, but few actually are. Having said that, most are within manageable driving distance. You'll pay a premium for those on Disney's doorstep.
Does your wife have a fear of flying? I attended a course a number of years which helped enormously, although the real cure is familiarity - more holidays to Orlando!

For years my Doctor prescribed Diazepam, although I've managed without for several trips now.
You've picked a good time to go - the weather should be good and the crowds relatively light. I'm not sure whether you're saying you're going for the period 9 May - 3 June, or that you'll be leaving the UK sometime between those dates. You might want to consider being back before mid-June as the US schools break for summer then. You're almost bound to get some rain in a sub-tropical climate, but we've been very lucky at that time of year. Even so, once you've got your trip booked, you should spend plenty of time reading these boards to pick up crowd-busting tips. As good as the DIS is, I'd recommend getting a guidebook too.
Ticket choices will depend on the duration of your trip. Can you clarify?