Let me start by saying that I don't believe any photo paper is a 'bargain'. When you can get 500 sheets of A4 copy paper for £1.99, i.e. 0.4p per sheet, I just can't see how photo paper can cost up to 100x as much, no matter what goes into the manufacturing process. It seems to me that it is the same as ink cartridges and they just charge what they like, as there is very little choice if you want to print photos yourself.
I am also not normally a fan of 'supermarket own brands, having bought the likes of 'own brand' shampoo in the past at 25% less than the branded products, because they contain 50% more water.
OK, rant over. Bearing in mind my observations above, this is actually a very good deal at an effective price of 11p per A4 sheet, compared to the competition. I bought a pack over the weekend and I am pleasantly impressed. The sign in store said reduced from £11 or so, which I took with a pinch of salt, but in retrospect is quite plausible. The thickness and quality appears very much on a par with HP Premium Glossy, which I have used before, but is around 4x the price.
It is available both online and in store (can be reserved and collected to save delivery charge) and if you need a good quality photo paper (and this is far better than the 'everyday' or equivalent photo papers) you could do a lot worse.