Thanks very much for the feedback.

The modem in the router is a CAT6. You’re right about the modem in my iPhone, apparently it’s a CAT19. I’ve arranged to borrow a CAT19 router from a friend to see if that helps at all.

I did consider that they may be checking MAC and prioritising phones so I cloned my MAC and it didn’t increase the speed any.

I’ll report back when it arrives and I have a chance to play!