I also remember seeing Yatton at the Octagon, from the balcony one could look straight down on it. It did show how simplified the trackwork was. As for which year?
I remember being at the Octagon with Burnham (P4), we had arranged for an excursion to Bodmin (P4), which comprised some through coaches. At the requisite part of the timetable, the train would leave Burnham metals, and get taken downstairs to Bodmin. Unfortunately one of the coaches was Chris Longley's, which had a habit of exploding - which it did in the hands of the late John Hayes! The look on his face when he came to apologise to be told 'oh it always does that' priceless!