Nicholas
I too would be wary of any self-proclaimed chief and would advise caution to anyone thinking about parting with their money.
There is an established process to obtain recognition as the Chief of a Clan through the Lyon Court. Quite simply, until such time as a claim is recognised by the Lord Lyon it is not legal/valid to use the title chief. Recognition by clan members is useful when petitioning Lord Lyon but it is not enough on its own. Proven descent from the last recorded Chief is necessary plus proof that all potential "senior" lines are extinct. Anything less is pure wishful thinking.
I await developments with interest.
Yours aye
Stephen