Update -
We've disconnected the WiFi extender and also undid the inside wall cable connector and did back up. Not redone outside cable connection as yet (sons!!!)
At the moment speed is back up to 200mb - realised I should have checked at each stage to be clearer on what might have caused it. Other son away working so need him back to set extender back up.
Tho we have been here before where speed is temporarily ok. Can we keep this open for a few days and I update you if it degrades again?
Jane