Hello mate , there is 4 Core plugs on the 1.6 cvh bottom end , there is three at the rear of the block and a somewhat larger one behind the flywheel. There is a notable difference in size and any good ford dealer should be able to provide you with one.
Heres some i found on ebay

http://cgi.ebay.co.uk/ws/eBayISAPI.d...ayphotohosting

Hope this helps

Ken