from what little I know,they were not often played together.Rabbidy Baxter used to acompany ScanTester[concertina].Will Atkinson did not accompany himself with a tambourine neither did Harold Covill.
IN Scotland the moothies,that I have met did not accompany themselves with a tambourine.
Buskers and one man bands like Don Partridge,[circa 1960 to 2008]normally accompanied themselves with a bass drum.