Somewhere for the UK Crowd. Blink Motorsport in Cheshire.
https://www.blinkmotorsport.com/
Damn good service and genuine good guys, they also know their stuff. Better known for their Naturally Aspirated work as they offer drive in/drive out packages. Anything Suspension or Engine, they've done it. They specialise in race prep too. They spend just as much time behind the wheel of their cars as they do working on others...
Got their "145 Package" with ITBs - car puts out 160hp~. No bottom end work. Wicked fast enough and as solid as a rock in terms of reliability. Faster cars struggle to keep up if the driver doesn't respect the importance of weight transfer.
Skuzzle Motorsport for those down the South of England. More "famous" as a company or shop, but never dealt with them myself. They seem to know their stuff too.