The two best places near(ish) Basingstoke rink are Everglides at Gosport and Skate Station near Bisley/Woking.
As regards sharpening, how often you sharpen depends on the amount of wear you subject them too, the depth of hollow and personal taste. Many people say every 20 hours or so. However, deeper hollows wear more quickly, and more energetic skaters will wear them more. I know a very good skater who sharpens them every six months, whilst skating 1-2 hours a week. I like newly sharpened blades, and give mine a single pass of the grinding wheel before every session (I have my own machine). I used to sharpen them every two weeks, which meant writing off a morning to drive to the shop.
I used to know when they needed a sharpen as I would start to slide sideways unexpectedly. I guess as you become proficient at skating, you learn to recognise when the blades start to lose their grip on the ice.