This has to do with VAT:

• If you order from a country within the EU, we have to charge the VAT rate of your country. This is a change in EU VAT legislation since 2021.
• If you order from a country outside of the EU, we charge zero % VAT. Note that depending on the rules of your local country you have to process the customs formalities yourself and pay local VAT, taxes and import duties.

We only know your country once you select it on the checkout page, That's why the price you see there can differ from the rest of the site. If you are logged in in your account, you do see the correct prices,

The UK is no longer a EU member. That means we would normally charge no VAT (to countries outside of the EU). But the UK has a different rule:

• If your order amount is below 135 GBP, we will charge (currently) 20% UK VAT. 
• If your order exceeds 135GBP, we will charge no VAT. Note that is that case you are responsible for import formalities and paying local VAT