£500+ believe me we have never spent anything vaguely approaching that
I have just done a whole class party which cost us quite a bit in excess of that after entertainer, hall and food for adults and kids, party bags etc. I also live in London and had to swallow the escalating cost. Siblings were also invited.
We started off with the hall and entertainer topping £350 then the rest just escalated.
We hired a hall because there is no way I want anybody in our flat, even though it is a good size. We hosted a small party at Christmas for 10 children and parents, never again. It was a mess and too stressful to organise in the lead up, we both work all the time and impossible to organise with kids wanting to play with you every second of the day.
We hired an entertainer and they did a super job entertaining 2hrs+. I do not want to be doing that myself at all. They took the stress away so I could do the 'good bits'.
We wont be doing it every year, but at this age (6) we thought this would be the one to do it and everyone had a great time, adults included. I feel it's nice to offer food to parents as well as children so that's simply my choice.
Would do it again even knowing the costs involved as it was easy, in terms of I didnt have to entertain one single person.
The LAST thing I am is a show off, far from it. I did the big class party because I felt it would be a nice thing to do and involve everyone instead of being selective for once.
Would have home party for a small handful of friends if DS wanted to, no issues there But I would prefer to talk into taking them bowling or cinema or football party.
It's not the 1980's anymore.
But you should feel no pressure, just do whatever you want to do and what fits in well with your family. Every party is different and there are plenty enough that are held at home too.