hmm ok... So at what point does a reversal become a trend change...

hmm ok... So at what point does a reversal become a trend change then? Was the Tuesday 16th November 2021 candle the start of the down trend? Wednesday 17th? If not, when?

I believe you can't know for sure until looking back in hindsight. We just make informed guesses until then. That is why, considering the discrepancies between the definitions/requirements of the pennants, the current IMU chart doesn't tick the boxes for a bear pennant, nor does it a bull pennant. So I'm struggling to understand how you are so sure it's bearish?

If you treat the higher high/higher low as a trend change (which is the definition of a trend change) it does tick all bullish pennant requirements and hence would be a continuation of the trend if it broke out upwards.

I agree that there is not enough information on the chart yet to confirm a trend change (higher high was not convincing and indicators lag), but that doesn't mean it hasn't. If the pennant breaks out upwards I think that would be enough evidence IMO to confirm a trend change. If it breaks out downwards then the downtrend continues, provided a new low is made.