Thanks for this.  I did find these two children also and did obtain a birth certificate for Rose.  I will need to find out if the 5th were in Cavan, Ireland  before the Mauritius posting.  
I also could do with finding out what happened to Rose's parents,  as in 1861 census she is living with an aunt and uncle called Desmond in Torquay.  When Rose is married in !871, her aunt is a witness. 
Last year I emailed the Mauritius record office details below 
MAURITIUS 
The Registrar of Civil Status 
Civil Status Division 
7th Level 
Emmanuel Anquetil Building 
Port Louis 
Mauritius 
Email address: 
civstat@mail.gov.mu-this information might be helpful to Alan
Cath