If using an Avios companion voucher...

[jobsjkfo]

....do you have to call up to book the flight? Looking at the app now and can't see anywhere to insert a companion voucher?

If you're booking a standard return, rather than an open jaw flight, you can just do it online. Go to your Exec Club page, select Book With Avios, and then you should have the option to add the voucher.

(I assume voucher available on your account, and not on a different family member's?)

I’ve never used the app but I have booked using the companion voucher online in the executive club section of their website

They charge more if you call!
You do need to be logged in to your Exec club account IME.

Thanks, it's on my husband's so I guess we'll need to use his account, I can never get the flipping website to work, only the app seems to work for me 🙄

That'll be the issue then - it's normally quite obviously there.