We have less disposable cash available than you do but I'm going to explain how we do it I case it's helpful.
I am also in the NHS and am 31 but I've been paying into the pension scheme for nearly 9 years. Absolutely join the NHS pension scheme as soon as you can. DH has a work pension that is rubbish but I have a decent NHS job so we accept my pension will be the main income in retirement.
Earnings: £5.3k
Direct Debits for basics: £2k
Variable bills (travel, groceries, pets, childcare): £1.8k
That leaves us with £1.5k. Of that, I send:
£100 to DD's savings (in an account I access so she doesn't just get her hands on the cash when she is 18)
£200 'slush fund' - this is for new tyres on the car, work required at an MOT if it doesn't sail through, work on the house eg. Electrics
£250 for presents - this covers all presents we buy for everyone across a year and means it doesn't blow our monthly budget in December for example
£250 into a holiday fund
Whatever is left we spend on whatever we want. I like moving money into separate savings pots depending on its use so we can keep track more easily. It's important to manage your cashflow well else you can easily fuck your budget, in which case, there is probably no point doing a budget in the first place. I don't go to the extent of budgeting for a hair cut or the specifics of certain things because that comes out of what is left each month and I get a haircut probably twice a year, it isn't significant on our income. But the like if presents do end up being significant, so I do include those. It's scary when you add up Mother's Day, Easter, birthdays, Christmas for everyone and their kids.