Well I would go on unbiased and find 3 firms locally and ring each and 'interview' them. This should be a relationship and not a one off meeting so you must gel. I personally wouldn't use anyone that wasn't Chartered, but I'm biased (I'm a Chartered Financial Planner).
If you need a trust you MUST have someone that has the AF1 qualification or is a member of STEP - much much more likely if they are Chartered. Ask them how they would go about setting up a trust, the questions they ask you will soon demonstrate if they know the area of planning and will def get rid of some IFA's.
BTL is for me an investment issue and needs to be viewed in the context of all other ares of your finances. It's good for some, but frankly an income generating investment fund would do the same job (and better) for some clients - again talk to the IFA and see what they say.
Trusts are going through a lot of changes and you'll need someone that knows and understands the impact of simplification (as and when, or indeed if it goes ahead). They will also need a strong law firm or use a firm like Solidus to provide trusts that are written with proper planning mind - not something your average high street solicitor will always do (I'll get flamed for that now!)
Pensions are more easily dealt with by a generalist, but charges here are important and again, it's not the only way to provide retirement capital (your tax position is the more interesting point here, plus your ages).
The CII (chartered insurance institute) website will also give you firms that you can contact. The CII is the leading professional body and is the lead partner with the PFS - personal finance society, from where we get out statement of professional standing, without which we can't practice.
All good IFA's will give you a free initial meeting, you've got to see the whites of their eyes to know if you can work together!
I wouldn't worry about swotting up - just don't do anything you don't clearly understand, is too clever by half, or makes you worry.