age 5 to 6. Boys kilt outfit (Park Road EH22)

Dear lovely people. My children are Scottish (I'm not) and they are super proud of it! We have the opportunity to go to a wedding and my nearly 6 year old son really wants to wear a kilt. I've been on the look out for something Preloved and have not found anything (been to a lot of charity shops). I do feel a bit out of my depth (and intimidated by the price if I'm really honest). Does anyone have anything? Or some advice? Very grateful for anything! I know it's a lot to ask. Much appreciated.