I'll second both the Napier gun mat and the H&N pellet boxes. I use the gun mat mainly for my shotguns and find it just a nat's thingy too short for those but it's fine for the rifles. The pellet boxes are great too for keeping either sorted/weighed pellets in good shape or for carrying batches of the right amount of pellets for your between-charges sweet spot.
The other thing I really rate is the Megaline hard rifle cases. I don't think they are common in the UK but I got one from the Bay of E. The good bits are: easy to clean because the outside is fairly smooth and not ridged, good steel hinges, the clasps are not aggravating like the Plano and Flambau ones, they just line up properly and work and they do cases that are shorter than the Plano and Flambau's which are more suited to our rifles.
The price is ok too.