I have one... not in a species tank. I've had freshwater for over 10 years... I have a bit of experience behind me. I've noted the 'fussy eating' and am about to locate a pipet to put the food infront of him if he doesn't eat by tuesday. All of my live feeders died overnight. I even opened the bag to allow gas exchange. As of current, I have normal aquarium gravel substrate, I'm contemplaing changing it.. but I want his stress level to drop a bit more before I go into that. I have a tank that's fully hooded, the thing managed to jump out yesterday. If my birds hadn't freaked out and brought me in there (I thought one of their wing's was stuck in the bars or somthing), I wouldn't have caught it in time. Since I covered the hole with plastic, as recommended, my temerature has risen to 78, 4 degrees higher... I'm trying to think of a way to get better ventilation. I live in the States... waaay far away from the UK. My LFS told me that he'd love me if I gave him live brine, but he'd take otherwise... but he's not eating at this time, we'll see how it goes.
edit-
lastnight before he jumped out, I noticed 3 spots on his back, and I hypothesize that they are a result of trauma when he was removed from the tank at the store. Typically, when this happens to my fish, they don't heal, get an infection and that's the end of it. But this morning, I looked him over, and they're gone, so I must be doing somthing right! =P