@NewportMichael As @bristolian has kindly pointed out THERE IS NO good (( indoor )) 4G/5G signal area, it's all a load off tosh from any Area map that Any mobile operator will say, all you can do is try to either find where the best signal is within your home, or try doing your External Arial experiment, if you do go down that route find an local expert they will guide you best for type/location etc, and THEN be prepared to run an Ethernet Cable from the Hybrid to the Router as the expert will more than likely want the Hybrid and the Arial up in the loft as high as possible....
