My list is slightly skewed towards dancers.....for obvious reasons

https://www.spotlight.com/artists/feed/ Paid for (£150?)
https://dancers.mandy.com/uk/dashboard Free month then paid for
https://www.mandy.com/jobs Free month then paid for
https://www.starnow.com/casting-calls/all/uk Can join for free but need to pay to apply for most jobs (£30ish for 3m)
https://www.talenttalks.co.uk/auditions/ Can join for free but need to pay to apply for most jobs (£10 pm)
https://talentstatus.com/jobs Can join for free but need to pay to apply for most jobs (£24.99 for 3m)
https://www.curtaincallonline.com/jobs Can join for free but need to pay to apply for jobs
https://castings.thestage.co.uk/auditions-acting-jobs Paid for
https://www.backstage.com/casting 6 months free then 6 months for £2
https://purpleport.com/castings/ Free (but can upgrade - first month free) Modelling
http://www.castingweekly.com/auditions/ Paid for (£2.50 pm)
http://www.article19.co.uk/audition/ Free
http://www.openauditions.uk/auditions Free but you must register
https://www.pineapple.uk.com/blog/category/auditions/ Free
https://maddog2020casting.com/en/ Can join for free but need to pay to apply for most jobs
https://www.musidac.com/ Free but you must register
Please add to the list or amend my details if you have better information