Why when no. of devices connected to ADSL has not changed and I have a tested and verified download speed of 5.6 mb/s am I suddenly now getting "insufficient bandwidth" notices and slow buffering when watching BBC iPlayer or Amazon TV?
so from that your problemis wireless and not dropping internet conenction
what have you tried to sort it? changed wireless channels as someone nearby may now be on same channel as you causing interference
which hub/router do you have?
Try a factory reset of the home hub.
Then turn off smart setup.
See if it helps to restore the bandwidth.