This morning I received my first answer.
Sian Flynn, the Surrey exile who is now Tory Candidate for North Cornwall, has replied saying that although she has not received any direct donations from Lord Ashcroft or his company...
"Conservative Campaign Headquarters (CCHQ) offers financial support to candidates in marginal seats from a central fund, drawn from donations to the Party from thousands of individuals. Bearwood has contributed a tiny fraction of this fund."
(I would dispute that the £10 million that Ashcroft and Bearwood has donated is 'tiny').
Bearwood is currently under investigation by the Electoral Commission on suspicion of not being active in the UK at the time donations were made and therefore breaking strict donation laws. UPDATE - Bearwood has now been cleared over these allegations by the Commission.
I'm still waiting to hear from the other five candidates.