Here’s a geeky point. A note I’ll keep to hand for advice.
I needed to keep my UK mobile number of 25 years, as some old people, old friends and potential work use it occasionally. They just wouldn’t ring a French number.
I’ve been paying £20 a month to Vodafone for virtually nothing, and although current contracts are said not to be in danger of being charged for roaming, I’m not sure if that will be true long-term, and I’m obviously in an inappropriate contract. In the distant past Three UK said roaming was free within reasonable use, but they literally cut off my line after 90 days in France even though I hadn’t used data more than once.
I also needed to have dual-sim phones, which actually hasn’t been a hardship or expense. £200 is not unusual for an Android.
My French Bouygues contract *does* have UK voice and data roaming, although not data sadly for the little-brother SIM in my iPad.
So I ported my UK mobile number to these guys who are extremely reputable tecchie niche suppliers, they were my ISP 25 years ago in the days of screeching modems. https://www.aa.net.uk/voice-and-mobile/number-porting/mobile-porting/
I can make and receive calls on my phone or iPad via an app (Bria from Counterpath, (currently $36 p.a.), via my PC and laptop, and also on old fashioned cordless and corded phones using a £40 Grandstream dongle that we’ve used for 20+ years for our Newmarket incoming number. In principal although simple one app running on a phone would make it indistinguishable for incoming calls.£1 a month, plus VAT, plus the minimal cost of calls. Obviously this is more about receiving calls and texts rather than making them. In fact I don’t think you can send texts, although you can receive them (useful for e.g. Banking two-factor authentication. Also you can’t by default make international (non-UK) calls, but then why would you. You have a local SIM in your phone with the appropriate contract for your needs.
Calls can be recorded and come immediately via email as mp3 files. Ditto received answerphone messages. The quality is very good, so far at least. As the quality of internet connection gets more and more bullet-proof, this can only improve.
This could also be useful simply to ‘park’ your number while you go away for a year or two, with the possibility of returning. You can always port the number back to Vodafone at any time.
No connection to declare, other than being a happy customer. Who makes mobile phone calls any more?