Not sure what you want it for, but have you tried Abranet instead of sandpaper. It' quite fantastic and once you have used it you wont want to go back to sandpaper again. Various grits from 80 to 600 and they last a very long time.
I've not specifically tried the "wet and dry" but the Titan brand is a budget brand rather than good quality.
I've used their standard Titan "abrasive" and it was not that good IMHO, the abrasive cracked and flaked off at the fold.
Used wet it is ok but does not last long before it breaks up/ wears though to backing paper. For wet and dry use 3m (bit dear but good wear) or indsa almost as good as 3m. The Halfords stuff is not bad either.
If you want decent wet and dry, get it from a motor factors or a steel suppliers - somewhere people who use the stuff for work get it from. That tends to be a reasonable indicator of quality.
I can't remember if it was the titan brand but I got some wet and dry from Screwfix a few years back and it was useless - the grits were inconsistent and I suspected that there were some over size pieces of grit on some of the sheets I had. Also, the grit didn't stay bonded to the paper as well as the sheets I'd had in the past (from Axminster I think). Most of is is either in the bin on a shelf somewhere gathering dust.