Reshaping aluminium frying pan

I hope this is the right place for this thread; if not, perhaps a kindly mod might point me in the right direction?


Anyhow, I've stopped my Mum from throwing out the old heavy aluminium frying pan that she got as a wedding present back in 1958, to go with her then shiny new Aga cooker.
The pan is 10"/255mm wide at the base, and has a heavy Bakelite handle.
It's in perfect condition, except that the base has gone concave (as viewed from underneath) from the best part of a half-century of making good old-fashioned agricultural fry-ups, and it no longer makes a good flat contact with the hot plate of the cooker.
It's thus pretty in-efficient, and has been 'in retirement' for the last few years, having been replaced by a new-fangled modern upstart sort of pan with fancy colours and non-stick stuff on it.

As I said, my Mum was about to throw it out, so I took possession of it and am pondering my options as regards rejuvenating it.

The base is bulged up by 8mm or so at the centre.

I have a pretty good selection of tools and equipment available to me, but I thought I'd get some other input before I take it to the anvil and the 2lb hammer.

I suspect that the aluminium is gone pretty hard by this stage, so I'm surmising that it might benefit from annealing before work commences.
If so, how might I go about doing that?

Anything else I should be thinking of?