So you need a monthly food budget from that, and money to cover:
clothes (including for growing teens)
clubs/hobbies
(annual bills like TV licence, insurances, AA etc?)
Christmas and birthdays
days out
meals out or coffees with friends or pints after work
books and school essentials including trips or tech or uniform
sundry expenses
pocket money for teens and treat money for adults
unexpected household repairs
any additional spending on decorating new house house/replace broken plates/want nicer curtains…
Im probably forgetting some other things you need to provide for.
Yes £2000 sounds like a lot, but I presume groceries for 4 is at least £500-600 monthly. (That’s only £125-150 per week).
Add in the cost of clothes that teens will wear. And how much school can cost in reality (and if it’s a new school, you probably don’t know all their traditional winter fayre, parent fundraising event, whole school gathering type things yet).
I would advocate trying to sit down and work out what you have spent in old location for the same period last year (use old bank statements) and how much you expect to spend now in new location, on a weekly or monthly basis. Split annual costs like birthdays, Christmas, annual fees, holidays etc over 12 months. Lay it out clearly and neatly for DH to see (and teens if useful and you see you need to cut back).
Show DH the reality of “if you have a meal with work colleagues this month, you can’t afford the March ticket and pints with X friend until next month” trade-offs that might be needed. And the reality of many costs increasing - some due to the move and some due to inflation and growing kids.
Perhaps (and I don’t mean this patronishingly but some people need things shown visually) set it out in pie charts or use Monopoly money to allocate to different envelopes and see what can move between envelopes to balance the finite budget. But maybe a clear list works well for your people so is sufficient.
And once you’ve worked out figures, sit him down and ask how he wants to balance the budget or if he’s willing to have no holidays or to run through savings in just X months, and have none there to replace car or boiler when needed.