Move closer to the router feeding the Roam’s signal? 

Or use bluetooth?

Thank you - but that kinda defeats the purpose of having a portable speaker?  Would be better just having a cheap Bluetooth speaker but wanted to link to my other Sonos products throughout my house.

The challenge may be (and it’s hard to tell from any information in your post) that you’re just too far away from the router that the Roam just isn’t getting a satisfactory amount of Wi-Fi signal. 
 

You may want to recreate the situation, and submit a system diagnostic within 10 minutes, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution. It may be not enough Wi-Fi, it may be something else. You’ve not given us anything to build a mental image on which to base any educated guesses. 

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

@BaxterM Isn’t that just what the Roam is for? Using wifi when you’re in your wifi’s range and bluetooth elsewhere?

Maybe the wifi coverage in your garden can be improved upon, so you could go that route too.