Punchy Dan:
Sounds like you have retro fit wheels and nuts ,the trims are for aluminium or steel wheels .I wouldn’t bother making the holes bigger unless you have a miller as if you use a step drill or cone you will need to be very careful or the trims will go round ■■■■■■ up when fitted but you wont see it just others going past will .
Thanks for the info. I’m hoping a local metal work company may have a machine good enough to enlarge the hole. Otherwise, a pair of black wheel trims going cheap if anyone is interested? Need to come to Holland to collect though. 