All TD4s up to about 2005 had the FBH. Mine does have one luckily for me. Mine was registered in March 2005. I know of a Jan 2005 that doesn't have one though
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As Tony said, the TD4 has it. The TD4 engine doesn't really get hot enough in winter to warm up the cabin effectively. So LR added a small oil fired boiler to help warm the engine in winter. Lots of diesel engine vehicles have them.
I've just added a remote to the FBH and some relays to the blower fan inside. This way I can start the FBH without going outside on a cold morning. The heater will then warm up the cabin and engine in advance of me leaving for work.
You'll have a FBH in your TD4 too