Ianh wrote:

Part 11 in the diagram ( LR041442) is the coolant temp sensor for a Puma 2.2 https://www.lrworkshop.com/diagrams/land-r...es_2.2tdci

Part LR041442 https://www.lrworkshop.com/parts/LR041442

Without a lot more info it’s hard to confirm whether the DPF light is coincidental, although the ECU may take account of coolant temp readings when instigating an active regeneration and if the coolant temp sensor or it’s feed to the ECU is in error it may prevent active regeneration taking place, causing the DPF to fill, and then causing the DPF differential pressure sensor to trigger a warning light.

Ianh wrote:

Check temp sensor wiring and sensor. Change sensor if faulty. Then take vehicle on 60 minute 60mph run to clear amber DPF light, if light does not clear, or worse goes red, then you will need a forced static regen via diagnostics tools.

Second diagram down shows wiring to test from coolant sensor to engine ECU https://www.lrworkshop.com/wiring-diagram/...e-controls

Ps . “Used on a sheep farm in wales” ...that could mean the engine has been running and not getting to DPF regeneration temp for a lot of its life, which could cause DPF clogging and cause hiccups as exhaust gasses will be struggling to get out of the engine.