From your explanation, It sounds very much like, either, your wife's solicitor has an extreme lack of knowledge about the UK, Spanish and USA law's and your own legal team was not of any standard expected, therefore I suggest the following to yourself which you may possibly find of interest/use;
- If you qualify for legal aid, find a well known/used and skilled solicitor and seek advice from him or her. If you are unsure as to how you would find a decent solicitors, try yell.com, ask any family or freinds whom you know have dealt with solicitors in the recent past. Look in your local newspaper, as solicitors quite often advertise themselves, however, after looking at what you have wrote, it does seem that there is a possiblity that you have paid for your legal team and if that is the case then I would strongly reccomend that you seek advice from your local citezen's advice as the best legal team to hire,(assuming that you did pay for your legal team)- you have already no doubt spent a substansial amount of money and still are left unsatisfied and feeling that they was not of a professional standard.
Also, I personally would be starting to write a detailed information log of the major contributing factors as to which would prove, that beyond ALL reasonable doubt, that both your solicitor and barrister acted in a such manner which was NOT of a professional standard, and there is a possiblity that if you have a watertight case then you could get a refund on your legal fee's which may help you fund a more adequate solicitors fee's.