Alarm horn battery problems?

Hi all, I've recently sorted out my faulty alarm horn and thought I'd just post it up in case it helps others......
I heard it was a common fault and that the battery would just need replacing but this doesn't seem to be entirely accurate. The common problem is that the backup batteries fitted tend to leak over time, this eventually seaps down the contacts,onto the pcb and destroys some tracks and components. If you catch it soon enough you might be lucky but alas I was not.
First the alarm horn will need opening, a hacksaw does the job....
Then you'll find this ...

And this is the damage I faced :

I had to fit two links as shown and replace three surface mount resistors that were damaged but having done this I refitted it and its working perfectly.
Saved me £ 88 for a new one and not that hard to sort out .......