If you are living in the UK or in the US or Canada, Brexit probably has meant nothing regarding prices on kilts and accessories. But to European Union citizens like me it has. Where it until January 1, 2021 was just about ordering what you wanted, pay at check out and wait for it to be delivered, it had not only become more complicated, but it has also made things from UK more expensive – and that despite the “free trade” agreed upon in the very last minute, so to speak.
Yes, there is no customs duty to pay when you buy from an English or Scottish seller – provided the good is manufactured in UK from components, made in UK. And how do you know?

Buying a kilt made in Pakistan from a British vendor means customs duty and VAT hereof. Fortunately, only if the price of the kilt does exceed 150 Euros equalizing about 120 GBP. And, fortunately, hardly any Pakistani made kilt amounts to that. But be careful not to order accessories together with it, which might also be “imported” and could therefore bring the total value above the limit.
And even if no customs duty applies, you must pay local VAT and a customs clearance fee, which might be around 18 GBP. Make sure that the seller has deducted British VAT, before you pay!
The VAT rate of your EU-country might be lower, the same or higher than the British VAT. But one thing is for sure, every online purchase in UK is now around 18 GBP more expensive than before Brexit. On a kilt costing 250 GBP it is 7% more. But on a sporran, costing 25 GBP it is 72% more!
Probably, spontaneous purchases by EU-citizens shall become rare. Unfortunately.