Every few months my "fairness" bone impels me to set the record straight. First however let me just say I do not work for Britpart but I am about to defend them.
1. As James says they are one of the main consolidators for LR parts. They sell all over the world and they do not sell to the public; trade, military or government only. It would be unlikely that they got to be this big by being rubbish at what they do.
2. They offer genuine, OEM, pattern and own brand. 4 choices, take your pick and pay your money. But when you pick something for 20% the price of genuine, please don't then embarrass yourself by moaning. What did you expect?
3. That said, their customer service and care is excellent. Some years ago I bought an alternator from reseller in Singapore. There was something wrong with it and one thing leading to another, the seller put me in touch with Britpart directly. Very straight forward interaction.
ME: Something wrong with this alternator.
THEM: Sorry to hear that, let us send you a new one. Where would you like it sent?
ME: Do you want this one back?
THEM: Lets get a new one out to you first and then think about it.
3. That said they were at one point sourcing so cheap that the quality did suffer and complaints did rise. Particularly on their own-brand stuff and especially with regarded to moulded or injected rubber and plastic bits. It looks like they sorted that, changed suppliers or something. Quality has improved (and prices have risen). The damage has been done, some people will forever more refer to them as ****part (!) but they do now offer a 24 month guarantee on their stuff. Just to compare, the official LR dealer near me only offers 6.
4. Their website is ****. They copy-pasted the stuff about cellular dampers from the shock absorber section to the steering damper section word for word!
All that said, re the actual steering damper, as Tony and others here have said, they are not critical provided everything else is up to scratch but since this is the real world and everything else will not be perfectly up to scratch they are an important safety and comfort feature. They should damp equally in both directions. Logical really that one! The point about oil is that if it gets very hot it will lose viscosity, hence reducing damping. And if it gets hot and gets churned around a lot it will get lathery. Provided of course there is also air. In a cellular damper the block of foam does two things, it gives the oil more room to spread and so to cool and it reduces the tendancy to lather. They are a good idea in suspension shock absorbers, especially if these are going to be worked rather hard. For the same reason however they are a bit of overkill in steering dampers unless you are doing some serious off-roading or rallying.