They were always in the UK Top 20 charts, and perhaps their "swan" song could have been The Carnival Is Over...However, i shall leave you with another song of theirs and a big favourite of mine...Notice again the use of a 12 string guitar played by the lead guitarist, those guitars always added an extra dimension of sound to the music, i bought my first 12 string in 1967, and i still have one of them now ..Funny you brought up the seekers when i was young played soccer with Bruce Woodley's son Dan and stayed over at their house a couple times nice family.
A bit of background in which he told my father and other friends he was shattered when Judith went her own way as there had been some disagreements i think it was over marketing. Bruce reckoned they would have been on easy street for the rest of their lives and as you mentioned internationally, if they had of continued touring and producing music as a band. Publicly it came out it was over creativity.
Bruce was advised to go into politics here and did so and won a seat im not sure how many terms he served but regardless they get a pretty decent lifelong pension for their service. On reflection in their house years ago just thinking about it now never remembered hearing any music and my friend his son never spoke of it.