So is it worth buying mid level (£3-500 to be specific) road wheels or am I better off not bothering?
For racing, I wouldn't bother. I've seen no evidence that anything under about £1000 (Cosmic Carbone, Zipp 101 for examples of where spending £1k does actually get you faster wheels) is faster than Shimano RS31, although the Flo30 might be the exception. For the odd 10 mile TT, £500 is most of the way to getting you some Raltech covers and a second hand Hed3, and not much at any price is going to be a lot faster than that. For road racing, you want something cheap enough that you don't burst into tears when they get smashed in the inevitable pile-up, so maybe drop down from the bling RS31 to the more affordable R501-30 :-)
For racing, I wouldn't bother. I've seen no evidence that anything under about £1000 (Cosmic Carbone, Zipp 101 for examples of where spending £1k does actually get you faster wheels) is faster than Shimano RS31, although the Flo30 might be the exception. For the odd 10 mile TT, £500 is most of the way to getting you some Raltech covers and a second hand Hed3, and not much at any price is going to be a lot faster than that. For road racing, you want something cheap enough that you don't burst into tears when they get smashed in the inevitable pile-up, so maybe drop down from the bling RS31 to the more affordable R501-30 :-)