Gail that worked a charm. I followed the steps you outlined:
Identify Page (using DBCC IND)
Took DB offline
Opened MDF in HxD and navigated to page(offset)
Added some garbage text and save
Brought the DB back online and ran DBCC CHECKDB (this clearly reported an issue)
Steps to remedy:
Back up tail of the log
restore DB page (the one I trashed) with norecovery
restore all logs and the final tail backup
DBCC CHECKDB reports no issue and the table contains the data I expected.
That was great exercise to run on my test DB and feel it's added a little something to my skillset!! I'll play about with different options (repair_allow_data_loss) etc just to see what happens.
Again, thanks Gail