Hi Tim,
I wish that I had something useful to tell you Tim.
A challenge you say. Yes, the expense.
The English archives at Kew, London are a delight to use mind you. Access is easy, they have camera stands and there are few delays.
I knew in advance the main tittles I was looking for mind you, then I did some fruitful searching there too.
The archives are near a tube station so you can find a cheap place to stay pretty much anywhere in London and commute by the tube daily; I did. But then there is the plane fare.
I think I used Air Canada to get there, to Heathrow.
Early Spring is when the plane fares seem lowest.
Hugh