Welcome to the Wefugees Communtiy and thank you for reaching to us.
The platform and our experts are based in Germany - therefore, we unfortunately might not be able to give too detailed advice on legal and residence questions regarding the UK or procedures in the Netherlands.
However, in this thread we discussed a similar question (and UK immigration issues in general) before - please follow the link for more information. On this website you may find details on the marrying process in the Netherlands and specific information for third country nationals.
I hope this helps and all the best,