There was a TV cartoon series called "Roobarb and Custard" but she's talking about the dialect.
I think she was just mischievously misspelling rhubarb. If anyone were to ask me which is Britain's rhubarb county, I'd say Yorkshire. I can sort of make Yorkshire dialect out of her phonetics. Did Maz actually claim it was Geordie (ie from Tyneside)?
Here's a link to back up my thinking - and just listen to the local dialect!
http://www.yorkshirepost.co.uk/news/...-day-1-5909947