I've downloaded the relevant 100 km square of OS Street View raster data and have added the relevant 5 km square to a QGIS 2.8.2 map of scale 1:1500. The layer can be seen in the layers menu but not on the map. I've tried adding the georeferencing data supplied by OS, but a message came up saying these are supported file types. I've also checked the CRS and it appears correct.
Move the .jpw or .tfw into the SAME folder as the raw tile (the .tif or .jpg file).
Add the raster layer (the .tif or .jpg file) when prompted, choose EPSG:27700 (British National Grid).
Right click on the layer, and choose zoom to layer.