We shouldn't all be taking an equal hit, those that can afford it best should be taking it. It isn't fair to expect those earning just above average, let alone below, to tighten their belts further. The fact is pensioners, higher earners, and those with assets/ savings are in a far better position to do so. And I accept that as a family with the latter two it's fair to protect those already struggling. I don't accept it's fair to do so to also protect the income and assets of a wealthier older generation.
Take the £13k example above for one pensioner, statistically more likely to be mortgage free or at least in affordable housing and have some savings too. It's certainly far from wealth and I'm not suggesting that's the group that should be hit. But by the same token, if we expect someone with 13k take home pay, with commuting costs, expensive housing costs, no free public transport etc and possibly a child to support as well, to cheerfully cough up more tax, knowing full well £13k pension is something they'll never see, then it's perfectly justifiable to expect the pensioner to take a cut.
Really, we shouldn't be looking at lower incomes at all. I would however be in favour of dropping marriage tax allowances, and in fact doubling the tax and ni for couples with one earner.
I would also ban most zero hour contracts and increase nmw as soon as the economy could take it. It would be a big saving, and easier than chasing tax dodges, if employers paid employees themselves, rather than relying on the state to top up low wages and precarious employment.