How to tell a fake Speedy reduced 3510.50?

I took it into TW Jewellers in Cockermouth and it was sent away by them to a watch maker. The watch was back with me within 4 weeks, which to be fair was roughly what they quoted. The issues with the watch were as follows: Losing time - 80-90 seconds a day, very hard to pull crown out to set time, rough feeling when winding, chrono buttons tight to push. All issues were fixed and it now runs at -10/15 secs a day