A Northern English way of saying 'How are you?'; used informally to greet someone with whom the speaker is on familiar terms. A comprehensive answer referring to the belly in question is not required or expected.
'Eh up Eric, how's your belly off for spots?'
'Now then Arthur. Could be worse!'
Messing about, fumbling, mucking about: particularly used in the north of England in a derogatory way, to describe some action the speaker believes is not being done properly, or is being done to slowly and inefficiently.
Kevin, stop tarting about and give me that spanner, you knob head. I'll show you how it's done!