Lots of these in the stream
No interactions present.
It certainly might be possible and Inopintaus IDed 2 cased caddis to genus recently. I wont attempt to but I would suggest a clearer pic out of the water might make it easier. An indication of size would be very useful also. There is a nice selection of illustrations of cased caddis larvae in 'Freshwater Life' by Malcolm Greenhalgh and Denis Ovenden.
The construction techniques of the various species are variable and they select different forms of building materials. I'm only scratching the surface of this interesting subject. There are a great number of different 'cases' to choose from.
A couple of out of water shots have been added in case that helps.
A really useful introductory guide to caddis larvae - particularly those in cases - is Ian Wallace's Simple Key to Caddis Larvae, published by FSC. It's useful for ID of many species or genera in the field mostly using features of the case or markings on the head.
Lat/Lng: 51.540316447216, -0.32921433448792
OS grid ref: TQ159837