Southwestern phonology: consonants TH

Southwestern accents, like those of Southeastern England, have sociolinguistically variable TH fronting. Wakelin (1986: 29) reports [f] for /θ/ in think, through and mouth for Bristol, as well as stopped pronunciations of / θ / and /ð/ as [d] in e.g. three, thistle, the, and then. There is, however, something of a lack of recent published research on this variable in accents of the Southwest.