Marcella Jackson chalkware figurine collection can be found here. The information I found on the web is below.
Marcella Jackson, a british subject, and Renato Migliorini, Daniele Magi, and Vasco Licci, Italian Citizens, all traded as M. Jackson & Co. They were based at 66, Rigby Street, Salford, 7, Lancaster in England. The earliest piece I have seen registered was from Januay 1960, and they kept designing pieces until at least 1965. By April 1965, Renato Migliorini was no longer listed as part of M. Jackson & Co.