Hi Peter,
I have the same problem with the timer. One off my resistors has burnt out. I have visited Maplins but they were of no use. I have eventually tracked down the resistor I need in America although it hasn't arrived as yet and I'm not 100% sure it is correct. The burnt out resistor on mine is the large one with the bands coloured Brown, Green, Brown & Gold. Below is a link to the site I found the resistor although they only come in packs of 50. The cost was still only $1.99 plus $4.40 p&p
http://www.opamp-electronics.com/~opamp/catalog/product_info.php?cPath=22_27_61&products_id=567
This link was for 10 at only at $1.49 so even better...
As I say I haven't received them yet so can't say it will work but will try to post the results - Good or Bad....
Gary W.
January 2008