For a 'cheap' British made after market shock that seems to last well, can be purchased with remote hydraulic preload adjuster, and is rebuildable by the manufacturer then my choice would be a Hagon. But I might be biased as thats what my bike is fitted with :mrgreen:
There's a couple of us on the forum with them, and as far as I know there have been no complaints. The two year unlimited mileage warranty is genuine as I found out when the seals on mine started weeping after it had been fitted for just over a year. It had done over 40,000 miles in that time but that wasn't an issue. All sorted FOC.
Although only having a basic damping adjustment, it easily copes with as much load as you can carry on the FJR, even trailer towing.
Other people will no doubt be along with other suggestions, but it all depends on what you mean by cheapish.
As to the load that the bike will carry, the official line is something like 10kg in each of the Yamaha side cases, and 5kg in the top box (but not at the same time). I weighed our luggage when we came back from our first trip around France on our non-ABS 2001 FJR and it came to over 50kg and apart from it killing the rear shock (hence the Hagon) our bike carried it without any problems.
You can find all the details by clicking on this link
When I last spoke to them about having the shock rebuilt they put me off having the work done unnecessarily. They were happy to do it, but in their opinion if the damping still worked, and it was oil tight, then it would be a waste of my money. Can't argue with that TBH.
Agree on the Hagon - mine doesnt have the remote adjuster though . The difference was apparent the first time i went round my favourite set of bends , before it sort of wobbled through , this time lot faster and over enough to drag my boot off the peg