The 2013 owner's manual says about the service light:
"...Illuminates when the engine is running to indicate a fault in the engine or transmission electronics.
The electronics switch to an emergency running programme, fuel consumption may be increased and
vehicle handling may be impaired.
In some cases, the fault can be eliminated by switching the engine off and back on again. If it illuminates
again after restarting the engine, the vehicle may need a service.
Have the cause of the fault eliminated by a workshop."
The burning rubber smell is a concern. The A12 has a lot of lay-bys and it might be worth pulling in once the vehicle is up to temperature, to leave the engine running for a look under the bonnet for anything that might be heating up.
For peace of mind it is always worth taking out a basic vehicle recovery insurance. I have found Green Flag to be a lot less expensive than (say) AA and RAC.
2015 2.2 CDTi SENav 163ps manual 4x4 in Carbon Flash with 19\" alloy spare towing a Bailey Unicorn III Madrid @ 1500kg.