Netherlands to UK can take upto 10 -12 business days at the MOST!.
Any longer and you can consider it seized/ lost.
When I used to order from there it took 6days at the most.
Can I ask why you ordered from the Netherlands with all the selection everyone has here in the UK?
Bit of a risk especially with custom seizures lately, we are leaving the EU so expect alot more packages to get searched / stopped.