Replacement lawnmower advice?

This is a venerable Mountfield, age unknown. It belonged to my late father and has been used to battle rough areas (brambles, cow parsley, nettles, etc) but has finally succumbed to rust - the entire corner fell off.

If I want something like for like, tough more than pretty, what's a good option in terms of make? Are Mountfield still good?

And, is this something worth buying from a dealer or does it make no difference?

I think folks may guess as what I would recommend but so long as a Mountfield is powered by either Briggs and Stratton or Honda motors you won't go far wrong.
That looks like a Tecumseh engine - long obsolete.
John

Dunno about obsolete. It started 2nd pull today after sitting in the garage all winter. Far as I know it's not had the oil changed or any other maintenance in a decade at least and it spent most of its years in Cornwall near the sea.

The engine is the only part of it that isn't broken!