Performance Pro - PRO1600PWA Leaking Gun!?

Hi, hope that someone can help. Went to use my washer today and although it worked, it was losing a lot of water through the gun handle. I have looked on a spares site and it appears to be a common fault. They sell a repair kit and for approx £7.00 (plus insurance, postage, tax) total £14+

Can anyone tell me if they have purchased this kit, was it easy to fit and most importantly... did it solve the problem. Your help is greatly appreciated.