Just bought a set of Nike sunglasses from Specsavers on their 2 for 1 offer (due for delivery on 9th May). My other pair are not tinted for day to day use (you have to pay extra for tint on the first pair), but you don’t pay extra for the tint on the second pair. Total cost £125 + eye test at £20 (you might be able to get this free with a voucher – I didn’t have one to hand when I went in).
I also have astigmatism & looked at buying contacts online & some regular sunglasses, but found the online places only do lenses in a limited range of prescription options (basically I couldn’t match my prescription online). According to the optician I would have had to have lenses specifically made to my prescription (though I might treat this with a little scepticism as they stand to benefit from me ordering the lenses through them)