Cheers dave the fuse appears to be ok. I also checked the main panel then I cleaned all the PIRS and door contacts making sure no webs or spiders etc. and that seems to have done the trick. 
As the tamper has gone off a couple of times without reason Should i be looking at changing the backup battery - Its been in their for 4-5yrs at least?
                
 HuggyTheBear
                
 March 2008