Thanks dylanks and stc
I think we decided not to bother with the RTS for now, just because I'll almost certainly be with her when she is travelling as we'll be heading to the UK together to visit friends and family - in those instances, she can come through the EU line with me. I don't see there being much value for our purpose/scenario right now. If we decide to move over to the UK then we might change our minds so she can pop home more easily and independently.
Hopefully those that have RTS are finding it a good use of money
Thank you for all of your insight!