Failand is a mobile blackspot with many indoor locations struggling to hang onto one bar of signal. This is because there are no nearby masts and the combination of hilly terrain and tree cover impede the signal. The situation is much worse than indicated by the network coverage maps.
With a smartphone you can use wifi ie your router. eg for Apple:
You can install the free OpenSignal app on your phone to find the nearest mast. Search the app store for "OpenSignal".
Search for the nearest masts at www.mastdata.com and see data by clicking on the icons.
The nearest mast is Orange/EE on the water tower in the small copse on the main road west of Horse Race Lane. The Vodafone mast indicated does not appear to exist.
You can create a "Personal Hotspot" with your mobile and get ~1Mbps with 4G which is useful if your main broadand goes down.