I would highly recommend buying an opinel in person. Some blades are warped more than others.
I wish I had that luxury. The nearest brick-and-mortar store that carries Opinels is almost 300 miles from me. Luckily, the (stainless) blade on my No. 6 is nice and free of any warping.
Since you want to buy online I see no reason to buy from just "UK" based online shops.It is not like amazon.uk's profits stay in the UK.There is a thread with various European shops that may help.Also amazon has several EU/worldwide sites and some may be cheaper, though there will possibly be import taxes etc.
You. This is all your fault with your variety of nice coloured ones