Found new owner
First of all, Parker conducted dating of products similarly to Dunhill: from 1925 till 1941, and then after an interruption - from 1945 till 1957. Secondly, old catalogues are interesting and useful indeed. Such Root Bruyere was published in the Parker's catalogue of 1955, but in the 1970's similar models weren't offered any more. So even the lack of a year suffix shouldn't confuse: the pipe was made after 1957, but not later than 1967 when models of Parker and models of Hardcastle were significantly reconsidered. Family traits, naturally, are present too: the group size, and the inner tube.
The pipe markings are"PARKER \ <ROOT> \ BRUYERE", "42", "MADE IN LONDON \ ENGLAND", "(3)". The length is 15.2 cm, bowl's hight is 4.6 cm. External and internal diameters of the bowl are 3.1 cm and 1.8 cm. The depth is 3.5 cm and this pipe weights 28 gr. Briar, vulcanite stem, inner tube.