Chocolate covering for fairy cakes - suggestions?

The original big birthday party for Gds is obviously cancelled - he’ll be 4 - but there’s a much smaller do planned, outside in the park near his pre school.

I’ve always made chocolate fairy cakes for their parties, with chocolate buttercream (and a Smartie!) on top - they’ve always gone down very well - but it looks as if it’s going to be very warm on the day, and buttercream is very messy anyway.

Any recommendations please, for brands of e.g. couverture type chocolate, that tastes as nice and won’t be as messy? I’ve not used that sort of topping for so long, I wouldn’t have a clue which is best.
Thank you.