Right of way and gate question

[Neolara]

We own a driveway that goes down the side of our house and leads to a plot of land owned by B. B has right of way over our drive to access the plot. His old gate collapsed and he wants to put in a new gate to the plot. He wants this gate to open outwards over our drive instead of inwards into his property. We aren't keen because when the gate is open, it will block the gate we are planning to install from our drive into our garden. Is he allowed to do this?

No. His ROW means he can only pass over your land. The gate will be a fixture on his land, and it cannot trespass over your airspace.

No - if you let him, it will muddy the waters as you'll be allowing greater rights over your property.