If you can post a picture of the marks on the handle it would really aid identification, but on the assumption that they are silver hallmarks (and I’m pretty sure from your description that they are), they show that the handle is sterling silver and assayed at the Sheffield Assay Office in 1972. The date code for 1973 also looks like an E but is in Old English script. I discount the Es for 1947 and earlier because of the brand name which appears on the blade. Note that the handle is unlikely to be solid silver through and through as they are normally only a skin of silver over a resin.
Yes almost certainly it was a promotion piece. If you want to know chapter and verse why not contact the company directly? - they have their own web site with a Contact Us link.