The short answer is yes it will work as a replacement as long as it has all the connectors you need.
When you say you took the PSU out and tried it and its still the same I presume it was connected to another PC? If not then theres no guarantee it is actually the power supply.
And no offence against Jeantech but for that sort of money I would be looking at something by a name better known to me like a Tagan or whatever. Also its a bit dear. As an example of a Jeantech PSU heres one from Novatech click here and looking at the picture of the 2 together it might be they are the same and the Novatech one is £15 cheaper, even with next day delivery you could still save a tenner if you can wait.