1901 Census - lost pages?

[Sass]

Would be grateful for any help.
I am really struggling to find details about my great grandmother, Margaret Ann Price. 
Have searched online on various different sites (NatArchives, Ancestry, 1837) for a particular address in Merthyr but all say it doesn't exist.
The address is 14 Ynisgau, Merthyr Tydfill.  I have even tried paging through all the census images around Ynisgau but this 'end' of the street seems to be missing? 
We have various family documents with this address on, including great grandparents marriage certificate in 1911.  My grandmother was born there in 1920 and she was told her mother was born there too (c1892 - although I cannot trace her birth certificate either).
I am not a novice at family history (although all previous experience is in England) but this lady is proving very elusive - does anyone have any ideas?

[nanny jan]

Could the street have been re-named or re-numbered?  It took me some time to find the stret in London where my grandpa was born because the name had been changed !Perhaps the local authority or local history society might be able to help you with the address.

Nanny Jan

[suzard]

There are 2 Margaret Ann Price birth reg on FreeBMD
Both reg in Merthyr Tydfil dist
Mar qtr 1892
11a 661
and
Sept qtr 1892
11a 6_9

Suz

[Sass]

Thank you both for your thoughts and efforts,...but
- in the 1891 census 14 Ynysgau exists and having checked the description of the enumeration district on both 1891 and 1901 they are identical - apart from the fact that in 1891 the return details all properties from no.3 but in 1901 it only seems to start from no. 27?! Unfortunately my family were not there in 1891. I wondered if the enumerator missed a bit or if there are pages missing/lost.
- I have both of the birth certificates mentioned....one is a possible but there are discrepancies which make me unsure - and I had hoped the census info would help.

Incidentally, does anyone know if Ynysgau Street still exists? I cannot find it on Multimap/Streetmap.com?

Many thanks again,
Sass.

[halfasheep]

A chapel noted on Ynysgau Street in the 1930s (dodgy photo - scroll down).
 http://www.alangeorge.co.uk/castlestreet.htm

I don't think this street exists anymore - excerpt from GENUKI (http://www.genuki.org.uk/big/wal/GLA/MerthyrTydfil/)

Ynysgau Cemetery, Merthyr Tydfil (NB. - this site disappeared in June 2006) - here (was) is a list of names from headstones later moved to other cemeteries.

(The graveyard was attached to Ynysgau Independent Chapel, which was built in 1749 and inaugurated in 1750. The graveyard was one of the oldest in Merthyr with some tombsones/monuments dating back to 1773 and 1776. The Chapel was demolished in March 1967 as part of the Merthyr Town Improvement Plan. The remains of those buried at Ynysgau Chapel were exhumed between 10th - 27th October 1969, and re-interred at the Ffrwyd section of the Cefn Cemetery. Many of the old tombstones were indecipherable with age and only some 49 names were legible. Unfortunately, the chapel registers have not survived, it appears that they were lost when the chapel was flooded (the chapel was adjacent to the River Taff). Further unidentified human remains were found at the site during excavation for a new road and were re-interred at Cefn Cemetery on 6 March 1998.
Allan Harrison, June 2004)