Originally Posted by IAN-UK

You might look into the difficulty of the airline carrying you into Dubai from Riyadh: it will see you as a one-way passenger who will enter UAE, and treat you accordingly- which will mean you showing the document necessary for entry.

If you have hold baggage to collect and check-in again for the London flight you will have to comply with the entry requirements.

In case you are travelling hand baggage only, a further concern is whether or not BA is processing Dubai-origin passengers airside.

All in all, It might make sense to de-risk the situation by giving yourself a generous margin to connect, and satisfy the emirate's entry requirements.