Gav, I had a play and whipped up a test "replacement" ULN3081. Looking at the Zaccaria schematics and also the spec sheet for a CA3081 I made up the board below using BC548's. If you would like to give it a try please PM me and let's see how it goes.

Holy cow... mate that is unreal!! I cant believe you did this.

Look , i would absolutely love to try it but the array i need is a 2081... my schematics state 3081 as does manual, but the IC's in place are a 16 pin package 2081... this is why i cocked up so bad... im reading schematics and testing pin outs only to find my board is bloody diferent.

Ive been onto www.pinballfixers.com
 Owen has all the Zac diagrams on there... cant see my boartd though with 2081 arrays and a cap tying TR4 to ground