A common way in which UK backers lose money is where the key onsite 'inside' partners have all invoices artifically increased and then pocket the difference.
Not saying there is any intention to manipulate investors here, but if I were investing I would want absolute clarity in the operating memorandum of agreement and for that to be bound by UK law and disputes to be settled in the UK only.
Honest genuine partners would have no issue with such an arrangement.
Another protection is for all works to be tendered to several suppliers well in advance and that all quotes have to be sent to the UK and then prices all agreed (as far as is practicable) up front. I would suggest UK partner representatives are also involved in sourcing suppliers such as architects.
A bonus structure for suppliers comming within budget and timeframes might also be worth consideration.
The suppliers would then be fed moneies gradually and contracts would seek to ensure no cost overruns were possible.
I know of 2 freinds who have both almost be caught out by this, luckily they spotted the over invoicing early on.