From the UK immigration website regarding UK ancestry:-
This page explains how Commonwealth citizens with a grandparent who was born in the United Kingdom may be able to apply for permission to live and work here.
If this page does not answer all your questions, you can contact us.
If you are a citizen of a Commonwealth country and one of your grandparents was born in the United Kingdom (including the Channel Islands or Isle of Man), you have United Kingdom ancestry.
You can come here to work if you can show that:
you are a Commonwealth citizen;
you have a visa or other form of permission to enter the United Kingdom because of United Kingdom ancestry, or your permission to stay here in this category has previously been extended;
you are aged 17 or over;
you have a grandparent who was born in the United Kingdom (including the Channel Islands or Isle of Man) or a grandparent who was born in what is now the Republic of Ireland before 31 March 1922;
you are able to work and you plan to do so in the United Kingdom; and
you can adequately support and accommodate yourself and your dependants without help from public funds (see rights and responsibilities for more information on what this means).
So - If you have Commonwealth citizenship, with your Scottish ancestry, you have a right to live & work in the UK. If you don't, you would then have to get a working visa. To get that visa as a pilot you would have to demonstrate that there was a shortage of qualified/skilled people for your profession
that is needed in the UK. With a number of pilots unemployed in this country you would be unlikely to prove a requirement.
As said in an earlier post, try the international divisions of the major companies. With a FAA licence +IR you should have little trouble finding overseas work, without the hassle of CAA/JAA licensing.
Good luck
902jon