If the county in a UK baptismal record is not explicitly listed on the current image but can be clearly determined from previous images which are part of the same set of entries in the record, should it still be entered as <BLANK> ?
My opinion: NO. If the previous image contains location information but the current page does not - my assumption as a researcher would be that the same location is implied for the current page or is a continuation of that previous location. I would assume this since location was entered on that previous page - and probably if subsequent pages are considered a new location could be viewed. A common enough assumption - I think - that it could be included in the Index.
If there are no other 'location' than in that area of the page for recording location - indicated in the previous record - then that also confirms the assumption.
If the Project Instructions or Location Entry Field Help state something like "... Don't use any other sources (i.e. other pages) to index this page ..." Then YES - unfortunately you would need to mark location entries <BLANK>.