Thanks for your reply.
The original has blown, though I have heard lots of people complaining about the Ashdown Blueline speakers as being junk so would be looking for something different.
Also I have been reading that the speaker needs to be matched to the capacity of the cabinet, which I think is relatively small in this case.
Basically I am looking for a 15 inch speaker, with at least 300w RMS, 8ohms for between £50-70.
Would you know anything that would fit this spec?
thanks