This episode may be one of the very best three or five episodes of the whole series. It's got all the well-loved 'Lovejoy' tropes: classic 1980s fashion (and cars); charming locations; an intense mystery centred on the actual antique item(s); Lovejoy skirting the law several times; a little too much closeness with Lady Jane; the viewers' first guess as to the culprit going completely wrong; know-it-all cops; snobby dealers; Tinker as the quiet expert; Eric stumbling half-wittingly over an important clue; and a finale in which Lovejoy holds all the cards, leaving even the viewer out of the loop till the end.
It's true Ian La Franais' script combines elements of several of the Jonathan Gash novels in one story (much as James Bond films are plot-amalgamated too); but the result is a cohesive story that includes healthy doses of esoteric details, good humour and real suspense, even life-or-death thrills. If you haven't watched 'Lovejoy' before, the first series is the very best of it and if you start with this one you'll be hooked on the programme for good.