Hi,
Wimborne library is much bigger and does hold a wealth of local information, old maps etc.
Phn: 01202 882770 or wimbornelibraryATdorsetcc.gov.uk * replace AT with @*
Colehill library is a "part-time" library 01202 886676 or colehilllibraryATdorsetcc.gov.uk
Priest's House museum 01202 2533 or priestshouseATeastdorset.gov.uk
failing those:
Dorset History Centre in Dorchester : 01305 250550 or archivesATdorsetcc.gov.uk
I hope one of those can help you; good luck!
Nanny Jan