Silver
I've done a mix of IR, PR and public affairs during my financial services career (IR and PA in-house, PR in-house and agency)
IR involves a lot of travel and above average amounts of entertaining, and I think MiFID II is possibly going to make this worse for in-house IRs
PA is probably the least amount of entertaining 'overtime', but is predominantly an agency discipline now, so would be mean lots of pitching and client entertaining, which takes up the house.
In-house PR for financial services can be long hours but the bulk of the heavy lifting will be palmed off to agencies. There is a degree of being able to cherry pick the travel and extra hours when you're backed up by a good agency.
Financial PR agencies will be doing lots of pitching and potentially long hours when working on big M&A and IPO projects
As you pointed out, post-Financial crisis, it has become a much more appealing career for people who want to stay within the City bubble (with City bubble salaries) but not at the sharp end. So standards have risen when hiring, and salaries at entry level are flat because there is an oversupply of new entrants.
Gross overgeneralisation alert:
I think the biggest issue for OP is that the career path is structured (or has come about by accident) so that the bulk of the long hours and entertaining is done earlier on. Win/win for the recent grads who are happy to eat and drink on the company dollar while on relatively low salaries, and enjoy the freebies and fun while your biggest consideration is juggling a hangover with an early meeting.
By the time you've risen through the ranks to be able to delegate that sort of stuff, you're also at the sort of age where a family might be on the cards, late nights in fancy bars hold little appeal and you can pay for your own social life.
Going in at the lower ranks in your 30s, as OP would be doing, means a lot of the grunt work and long hours, at a time when it might not be so appealing to be doing shots with recent grads and trainee journos
But the same would be true for any other career shift within the wider world of financial services...
Perhaps with the exception of trading, because they never seem to grow up and slow down