Legal ownership

A couple of things spring to mind. 

Are they paying for their 50%? If not are you not effectively gifting them 50% if you name them as co-owners, which could cause issues with inheritance tax if for some unfortunate reason you don't live very long. I think professional advice is best.

If all 4 of you are owners you will probably need to do 4 tax returns which is PIA quarterly if you rent it out :-)

You would be tying them to legal obligations in Spain.

Suggest you leave it up to them to decide if they want the house (or to liquidate the asset), hopefully a long way into the future.

Suggestion ... if they are paying the 50% cash (between them) towards the purchase, make over an equivalent value of your UK home to them, so they have something for their money. You can retain right of abode.

Hi,

Yes they are paying 25% each from their own funds with my wife and I paying the remaining 50% between us , however we will probably walk away from our share in the future and leave our 50% for our sons/grandkids , would we be better just putting it in our sons names , leaving us off the deeds completely now and therefore avoiding any future problems! The only thing is we will probably be using it more than our sons at the minute and would be more available for any legal duties etc , this could be a problem if we are not legal owners ? 

It's a minefield and I would seek professional advice from someone with expertise in Spanish property law. A few quid will be well spent and may save a lot of aggro and expense later. I presume you will also be making Spanish wills?

Owning property in Spain means fiscal obligations. Non-residents need to appoint a "fiscal respresentative" and file yearly income tax returns. Whether or not you include descendants in your deed, I strongly recommend setting up a standard will at any notary public which should cost not more than 80,- Joint spousal wills are not acceptable in Spain.

Already mentioned are the fiscal requirements for property owners in Spain. However, there are UK matters that need to be considered. None of these scenarios are ones anyone would wish for, but life does sometimes throw up difficult times.  Your children will own an asset that can be taken into account should misfortune come their way. For instance, if they are made redundant then the asset could affect the benefits they would otherwise receive, or if they were declared bankrupt then the asset is again a matter of interest to the courts. If your children are married (you mentioned grandchildren) then if one couple divorce the asset could be considered in the divorce settlement.  I sincerely hope none of these happen to your family, but you do need to be aware of all the implications. I recommend taking legal advise on the best way forward to protect you all in the long term.

One vital thing to consider. Your sons are young and probably unmarried. Should they marry and sadly divorce, their other half will demand her share of the property. Someone of you will have to cough up the money. When we bought 20 years ago, my husband suddenly decided not to put the house in our children’s names but keep it in ours in case of unforeseen situations. People we know in Tenerife put their son’s name on the title deeds, he divorced and they had to find quite a large sum to pay his ex wife as they didn’t want to sell their gorgeous place. It’s food for thought. Your solicitor could offer the best advice on this issue.