Here are a selection of websites, recommended by Heritage Lincolnshire, which you may find useful when conducting further research about Harlaxton Manor.
Heritage Gateway http://www.heritagegateway.org.uk/Gateway
National Heritage List for England. Tip: carry out an advanced search, set map area and view the results on a map. Click the ? button for further detail.
Lincs to the Past http://www.lincstothepast.com
Operated by Lincolnshire County Council, lists items held in the Lincolnshire Archives, of particular interest in the Pearson Gregory Collection.
Cambridge University Aerial Photograph Collection
http://www.geog.cam.ac.uk/cucap
Able to view photographs by browsing a map, there are some of Harlaxton that can be viewed but you have to pay to download. Here is a starting point: http://www.cambridgeairphotos.com/location/fp51/
Britain from Above http://www.britainfromabove.org.uk
No shots of Harlaxton but interesting aerial views of Grantham. Register to gain access to higher resolution.
Artefacts
British Museum http://www.britishmuseum.org/research/collection_online
Portable Antiquities Scheme website http://finds.org.uk
National Trust Collections http://www.nationaltrustcollections.org.uk
Some interesting photographs of houses in the village.
Standing Buildings
Historic England https://historicengland.org.uk/listing/the-list/
Tip: use the map search tool under the search box.
Buildings at risk register http://risk.historicengland.org.uk/register.aspx
Tip: search or download the East Midlands list.
Historic England Photograph Database
https://historicengland.org.uk/images-books/archive/archive-collections/Englands-places
Includes some interesting shots of the Manor and village.
National Library of Scotland Historic Maps http://maps.nls.uk
Database of historic maps with an interesting View side by side feature allowing you to compare old maps with modern satellite imagery.
Other research
Google Scholar, a Search engine for finding academic articles. http://scholar.google.co.uk
British History Online, primary and secondary sources but not many relating specifically to the Manor http://www.british-history.ac.uk/Default.aspx
The above list was compiled from a “How to find history on your doorstep” event presented by Ian Marshman, Heritage Lincolnshire, 29 February 2016.
Other resources
Archaeology Data Service http://archaeologydataservice.ac.uk
This record is of interest:
Probable Prehistoric or Roman enclosure and boundary ditches seen as cropmarks. http://archaeologydataservice.ac.uk/archsearch/record.jsf?titleId=1299764