Don, Thanks for that information …. unfortunately, it is as I feared.
We do have a carbon monoxide detector in the kitchen; but that is because we have an oil fired boiler in the kitchen as well. The Bosch hob is run from Propane gas, not natural gas; not sure if that makes a difference ?
But, many thanks for replying. Just hope there may be someone with a similar model rusting away somewhere …. who knows. Thanks, DDDerrick.