Python Plotly Dash Django testing daylight savings time

I have a time series data base where datetime is stored in UTC. A Python Dash date picker and Text box allows selection of date and time.

The pandas DataFrame is made timezone aware and used as the x axis as follows: x=df[‘cdatetime’].dt.tz_localize(‘utc’).dt.tz_convert(‘Europe/London’),

The chart and map plot the data correctly, showing times in the correct locale which is currently BST. However I want to test if it still works when daylight savings time ends and locale timezone is GMT.