Being a British citizen, and living in Spain, I get asked all the time by people still in the UK, or living here with property in the UK about financial arrangements, I try to give the best advice I can but I'm not a legal expert, and with property, proper legal advice from a trained professional should be considered mandatory, and not something left to chance or the advice of friends.
Let's forget about property in Spain, and focus specifically on property in the UK, especially selling property in the UK. Whether you're downsizing, moving to another city, selling a property to reinvest the asset, looking for first or second mortgages, at some point you are going to need the services of a conveyancing solicitor.
I'm not sure if it is possible for a layperson to transfer property, at any event the task is so complicated, and worse, fraught with additional costs and liability, that not doing the job correctly and according to the law opens the vendor up to all sorts of not so pleasant legal action if something goes wrong. Worst case scenario the vendor could literally lose the entire sale price in damages and legal fees.
For this reason, and read this carefully, I strongly recommend seeking the advice of a qualified and experienced solicitor. These are people who understand the property act, they know which tort opinions apply in your case, they understand the regulations involved in property conveyancing.
In the past I've tended to deal with solicitors who specialize in conveyancing, they're easy to spot, they proudly advertise the service, and they usually have at least one or two clerks with experience of conveyancing. Contrast this with family law, or trusts and wills solicitors, who whilst being good at what they do, just don't have a passion for property.
All of this advice I'm going apples equally to buying property, except purchasers often have more to worry about, is their deposit protected, is the home they plan to purchase structurally sound, has a home survey been done, is title to the property exactly as the real estate agent or vendor have described it, are their any charges outstanding on the property.
I'm sure you'll agree this minefield isn't to be negotiated in an improper manner, or by leaving to chance that everything will be OK. Remember, the real estate agent and vendor don't have your best interests at heart. Consulting a your own house conveyancing practice is the only option for ensuring your life savings and future mortgage payments aren't going to be wasted on a home that isn't worth what you pay for it.
Remember, for most people the capital tied up in property represents their biggest asset, or biggest portfolio, and frankly, the cost of consulting a professional to undertake the conveyancing cannot be measured in money alone, peace of mind, the promise of a painless transaction, and the cost of unneeded stress need to be weighed as well.


