BA Avios query - domestic connection?

[decena]

Hi , I'm about to book my first ever reward flight using avios and companion voucher. But the BA app. only let's me put in the long haul, how do I add the domestic connection to Gatwick? I want both flights on the same ticket in case of delays.
Or do I have to phone? Which will be a bother as we will be abroad at d-355 days when I need to book.
I also have 2 companion tickets - me and husband. How do I get both vouchers to show when booking on line?
Thanks.

You have to phone. Their online system is shit and can't cope with anything other than a direct flight in and out of a single airport.

I phone at 6am 355 days before and book the outbound leg then again 355 days before the return.
You do need nerves of steel, but can cancel the outbound for a small fee, if there's no availability.
Those reward flights are tricky to find, at least for any destinations I want to go to. Good luck.