6 year old birthday party solo mum

[Sakura03]

DC's birthday is coming up, last year he had his first party, his dad was meant to go half so we hired private soft play, however things didn't go to plan so I forked the bill myself (£400🙈). This year we'll invite 8-10 friends but soft play and gym sessions still seem expensive. We have a small home but could have 6 children round, there is a large playground/park nearby so could do a treasure hunt there. I'd be happy for parents to do drop off but not sure parents would want to as we still don't know each other that well. What else entertainment do I need? I think I can only pull it off if i can get a friend to help but was thinking it would cut the costs down, however, is it worth the hassle? Any thoughts, tips and ideas please? Or should I just bite the bullet and book somewhere?

Is there another class member you can do a joint party with

I ( lone parent ) had a couple of make your own pizza parties at Pizza Express ( I think ) when my ds was around this age. They were good fun, parents could come and have a drink if they wanted, and obviously the children took home any uneaten pizza. No mess, not wildly expensive, made their own food, all I had to do was turn up and have a glass of wine. Job done.

not lone parent but trying to stick to budget. we have hired a local scout hut for 65 quid which comes with bouncy castle included and teas and coffees for adults.
some we have been to have added an entertainer but they are so expensive so we are just having it as it is and will supply a lunch and party bags.
do you have anything similar nearby?