I have used genieimaging, they were good. More recently I have used "The Darkroom UK Ltd" who charge £4.50 for processing only. This price includes VAT and postage both ways so the cost is comparable to Genie when you add these elements in. The last 3 films I've developed myself which is cheaper again. Once I have the slides or negs they get scanned on an Epson V700 - expensive to buy but I wish I had got is sooner to cut out the costs of scanning by labs sooner.
Labs often quote a price for scanning which is only for a fairly low resolution and the cost spirals once you go to a higher resolution. Scanning at 3200 dpi with a 6*7 negative results in an image file around 56mp which is easily achievable with the v700.