I want to set up a company providing film consultancy services across Europe and later further afield; I work from my laptop and am trying to decide whether or not the best option is to register the ltd company in the UK and work as a freelancer paying taxes either in Spain, Germany, France or Croatia? Which of these countries is the most advantageous for an independent professional? I could legitimately live in any of them for 183 days a year.
You've got 2 tax issues here:
Firstly, if you're opening a UK company it will be liable for tax in the UK on all its profits. If you're doing more than that VAT thresholds worth of work (about 50K) then you will need to register to pay VAT on this (Registering VAT). You'll need to do this even if you're getting work from other European countries. It doesn't matter where the work for the company is being done, it's where the company is based.
Your personal tax rate will vary from country to country. It's at this point things get interesting. In the UK people tax most of the money from their company in the form of dividends because of the tax advantage (no NI to pay, no tax on the first 35K, then 32% on the rest). This may not be the case in other countries. Germany and France are known as "high-tax"; Spain is in the middle of a debt crisis so expect the government their to start closing tax loopholes.
Your best bet is to sit down with an accountant. I use SJD, who deal with exactly the kind of company you want to set up. The initial meetings are free, they can set the company up for you and do most of the paperwork.