https://www.tubewaysales.com/cat/easyfix-secondary-glazing-systems/easyfix-stick-down-secondary-glazing/easyglaze-secondary-glazing/
Easyfix DIY Easyglaze Adhesive 2 Part Rigid Secondary Glazing
Adhesive base sticks to window surround, glazing inserted then top clicks into place for attractive heat and noise insulation. See video and instructions
easyfixdiyadhesivepartrigid