Canon, wouldn't buy from jessops, London camera exchange are good. Get one with the highest Mpixel you can, usually circa 18 mp. Also you need a full frame camera.
Lens, what you want to shoot? Landscape, macro portrait? A good glass will cost more than the camera, if going Canon route, look at the Red banded lens. These are the flagship lens. Entry level is the silver banded lens.
tamron lens is suitable for everyday stuff inc 2:1 macro shots. Basically a macro shot will be half size and not 1:1 scale.
Tripod possibly.
Tamron, 18/300 lens is ok. Canon 18/55 lens quite restrictive IMO. Also apature on the lens is important, the smaller the f number the better results. Small f = wider opening, however best f number is between 8 & 13, in this area you don't get much vignette. ( a darkening around the outer edges of the picture)
Any more info, pm me