I've been using Google Voice (formerly Grand Central) for my primary contact number for years. The integration with hangouts is mostly complete now, and not a bad way to interact.

I can check my voicemail via my computer or an app on my phone. They also transcribe the voicemails, as well as offering blackout times, and buckets for different calling numbers. If it's from a cell phone, I can directly reply via text.

During the day, at work, I pretty much ignore my phone, and send all calls to voicemail... being able to quickly see and reply is useful (though sometimes the transcriptions are particularly bad).

There are/were other similar services to this out there, not sure what's available in the UK, but you may want to look into it.

You missed the part where voicemails are emailed to you transcribed, integrating nicely with Gmail. All of my voicemails are in Gmail, which is perfect for Inbox Zero GTD.

Yes, forgot to mention that option, as I don't use it... I've pretty much gotten used to the Hangouts integration at this point.. except the outbound dialing, it's gotten very decent. Hopefully they clear up a few of the dangling quirks.