Mobile hotspots and 4G routers are not officially supported, but you could always try it. Depending on the service and speaker Sonos may buffer sufficiently to ride out latency spikes. 

Is it something that I should try then? 4G mobile broadband would certainly help with other internet use at home, the only thing stopping me is the Sonos issue as I have a fair few speakers that I am loathe to offload 

We are with EE for our phones, surely they as a company would be a safe bet?

I can’t comment on EE’s service at all. Unless you can get a decent internet service from BT (a relative has 150Mbps fibre to a rural location a few miles east of you) I would just get a 4G router and try it. If Sonos struggles then Tech Support might refuse assistance, but it’s worth a go if you’ve no alternative. 

My system ran on a 4G service without any problems for 2 years until I recently got FTTP 

Our BT speed of no more than 2mbps certainly is veering me towards a mobile internet provider

I used 3G for a solid two years 10 years ago without issue, obviously not streaming CD quality. Used to get about 5Mbps whereas fixed line was 512kbps.

Not obvious at all really. The recommended bandwidth for one FLAC stream is 5Mbps, which is for bursty buffer filling. The sustained bitrate is ‘only’ around 1-1.5Mbps (allowing for overhead).

You’ve lost me now with this tech talk…

Yeah but I needed the rest of the bandwidth for the rest of the family hence I chose to go lossy.

It was a typo..goes off and mumbles something about kilts and bagpipes…

There seems to be some confusion: lossless is CD quality. Anyway let’s not take this further off topic.