Money Diary: A 27-Year-Old In Banking On 200k

Welcome to Money Diaries, where we're tackling what might be the last taboo facing modern working women: money. We're asking a cross-section of women how they spend their hard-earned money during a seven-day period – and we're tracking every last penny.
This week: "I moved to London nearly six years ago, straight from university. I was hellbent on independence post-graduation and my rationale at the time was that if I didn’t know what I wanted to do, I might as well get paid as much as I can while I figure things out. As it turned out, the banking job I landed out of university wasn’t nearly as bad as I thought it was going to be, and I’ve stayed in the industry ever since.
I recently bought a flat in central London with my boyfriend with no help from either of our parents. The deposit and refurbishment costs (it’s a bit of a doer-upper) took a healthy chunk out of our savings, which was a bit scary, but I’ve since managed to rebuild them thanks to last year’s bonus.
Day to day, I’d like to think I’m pretty good with my finances. I grew up in a relatively low-income immigrant household where some degree of penny-pinching was the norm and nothing was taken for granted, and this has rubbed off on me. I keep an eye out for good savings accounts, have recently started taking lunch into work, and spend more time than is normal thinking about my pathway to retirement. That said, I do frequently succumb to 'treat yo'self' moments, which my parents would definitely frown upon, if they knew..."
Industry: Finance
Age: 27
Location: London
Salary: £100k + £100k bonus
Paycheque amount: £4,400
Number of housemates: 1 (boyfriend)
Monthly Expenses
Housing costs: £1,260 mortgage (split equally between me and BF)
Loan payments: £70 minimum payment on an interest-free credit card, where I've put a selection of random large purchases. It's nearly maxed out and I'm in no hurry to pay it off – it's interest-free for another two years, and I have enough savings to cover the amount outstanding. I put the money I would otherwise have spent into a savings account instead, so I basically get free money through interest arbitrage. I paid off my student loans a couple of years ago.
Utilities: £380 for council tax/ internet/ gas and electric/ service charge/ TV licence/ home insurance (all split with BF).
Transportation: £80. I top up my Oyster on an ad hoc basis (I have my 26-30 railcard linked to my Oyster, which gets me 1/3 off during off-peak hours).
Phone bill: £69
Savings? Varies month on month, recently it's been around £1,000 due to holidays/ redecorating, but hoping to increase this in the next few months. £400 goes into my pension (taken directly from my paycheque), but this works out to around £1,000 into my pension pot once taxes and work contributions are taken into account.
Other: £50 taxes on private health insurance through work (taxable benefit), £35 ClassPass, £50 local gym, £15 Spotify Family (split between myself and BF), £7.99 Netflix, £14 contact lenses, £0.79 iCloud subscription, £80 cleaner.
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