Welcome to the forums. While some additional pictures, including an overall picture, would be nice, there is sufficient evidence to state that this is a mass produced bicycle and not one built by Jocelyn Lovell. While you may not have seen this particular lugset on Nishiki, it must be remembered that Nishiki was not a manufacturer but a marketing brand that has been manufactured by numerous contractors over the years. To complicate matters even more, the brand often had different owners depending on the country and each owner would design their own bicycles. Consequently, a specific model, say a 1982 Nishiki International, would be different for the Canadian market than the USA market.

Link to OP's photo album. https://www.bikeforums.net/g/picture/15400231