its not a case of £44 unit
If they had laid 2 wires along the track for a cost of £88 then the theives would have just doubled their profits.
When our signalling cable was stolen they got it working again in less than a day. That is Discover fault in morning, run some tests remotely, find send crew out to see why failed, crew measure how much wire is missing crew call back that wire is missing, send another crew with skills and materials to fix wire, fix wire, test wire, check safety, get trains and crews back to where they should be.
Also should not just look at cost. If I took six £0.20 bolts of the hub of your car even with triple redudency then your car would be useless until you fix it.
I hate train ompanies as much as the next guy being on southeastern, but this is one fault that should lie with the theif not the network.