I use the Autotrader valuation tool to keep an eye on prices. I use the Part exchange figure as a benchmark
Jan 2021. 38600 miles: £20,910
Oct 2021. 43000 miles: £ 25,150
That lift seems to match the prices I've been hearing about on this forum. Of course it is all artificial until I actually choose to sell, but it might be tempting to trade it in against a £31,000 GR Yaris