Hi Donna
Perhaps this is Eliza in the 1871 Census (on ancestry)?
Name:Eliza Halliday Age:17 Estimated birth year:abt 1854 Relation:Housekeeper Gender:Female Where born:Ireland
Civil Parish:Iveston Ecclesiastical parish:St IvesTown:Iveston County/Island:Durham Country:England
Registration district:Durham Sub-registration district:Lanchester ED, institution, or vessel:15
Household schedule number:65Piece:4959Folio:135Page Number:13
Household Members:Name AgeHammie Swalwell 81 Eliza Halliday 17
If this is not your Eliza, free UK BMD only has death reords for ELIZABETH Halliday - no Elizas in Durham. I searched 1859 to 78 & found 7; there are more in later years
Halliday Elizabeth Sunderland 10a252
Halliday Elizabeth Gateshead 10a305
HALLIDAY Elizabeth Ann 4 Easington 10a197
Halliday Elizabeth 55 Chester le Street 10a298
Halliday Elizabeth Ann 0 Stockton 10a95
Halliday Elizabeth Ann 0 South Shields 10a371
No ages are given. If any is from an area near where the family was in the census you'd need to chase the certificates up through the GRO.
I had a look at the England Censuses 1861, 71 &81 for Elizas with the married names Elwyn found.
The Watson & Lee Elizas were born in the UK; the Ormston Eliza was Elizabeth Ann & Humbleby didn't show up at all.
She is elusive!!
Col