Hmmm......I just looked at burials in Shiplake. There are entries for a William and an Elizabeth, but if their ages are correct then they are borderline too old (or she is).
1831 Elizabeth Morgan aged 88 (so b abt 1743)
1816 William Morgan aged 78 (so b abt 1738)
It does potentially fit I guess.
Eliz b 1743 married the first time aged 24 and has these children, bap in Caversham:
Mary bap 2nd Oct 1767 poss burial 28th Jan 1770
Thomas bap 6th May 1770
William bap 5th April 1772
Robert bap 26th Jan 1774
Anne bap 31st March 1776
John bap 7th June 1778
Mary bap 27th Aug 1780
She is then widowed aged 38, has another child aged 42 who is bap in Caversham
James bap 2nd Jan 1785
Remarries aged 45 (thinking she won't have more children??!) and then aged 48, has another child, Rose Hannah, in Shiplake.
I guess there's a chance by the time Elizabeth reached her 80s she started to gain years more quickly (!) so had she married the first time aged 21ish then the chances of a late baby aged about 45 is probably more likely than 48. Or, maybe Rose Hannah was born slightly earlier than I think, or both!
Another option is a burial for an Elizabeth Morgan in 1789 in Shiplake (no age).
Now, how to go about trying to either eliminate these people or prove they are Rose Hannah's parents/relatives?......
First off, I don't know that I want to spend £17.50 for the transcripts of the PRs for Shiplake to (hopefully) see Rose Hannah's baptism.
Why is everything to do with Oxfordshire so expensive?