Paul, I was in Daves of middlewich today and they had some fork headed bolts that may be what you're looking for, ? 3.50 each I think they were. They also had the thumbscrew bolts to hold them in the alarm body. Phone no. is 01606 833853.
Hi Paul 2 I`ve got a metal opti-polo if thats what your looking for or an other option is to get one from the perica 1000 bite alarms do the same job mate.