Mannin Collections used to deal with high quality 2nd hand books - no longer does so as the market is now too small (competition from ebay etc).
Adam Caine was grandfather to Adam - I have the line worked out - and will be updating the pages in the next few days with both earlier and some later info.
I doubt if Wendy would have time for tea during her busy working hours - she is an archivist with no special interest in family history other than knowing which records the Museum holds - try IoMFHSoc once you have joined