Interesting! The census won't be able to help, i suspect, because if she married a Mr Raby, it would be after the 1923 death of her husband, and by 1928 she has passed away and Mr Raby predeceased her, if there was a Mr Raby.
Here is a pic of the memorial marker that was erected honouring her husband and saving a space for her. Note that the date of death has not been filled in on the grave marker. Maybe the cemetery itself will know whether she actually occupied that space.
Did any of her children marry a Raby? I'm just wondering if the person who filled in that part of the death cert accidentally transposed something - the name of the cemetery, or the name of someone in the room at the time...or the next death being registered...
In any case, it will be a very short time period to search for a second marriage.
I will keep looking for that marriage.