and having the iPhone automatically call John through DISA,

you'd call your Twilio access number and then enter John's number.

However, we can improve that substantially.

For example, an iPhone shortcut could take a contact number

and initiate the process,

potentially with Twilio doing the second leg automatically

rather than requiring you to key the number manually.

I think it's worth designing this properly before you buy another SIM.

The first thing I'd test is the critical assumption.

Twilio your existing mobile,

with dial preserving the original inbound caller's CLI.

If that works with your UK mobile carrier, the rest is straightforward.

If you want, I can give you the exact Twilio configuration for that first test.

It should only take about five minutes.

It doesn't require touching freebie.

Yes, I do want to do that.