Or, another option is to jump on the bay and look for something like this.
These are off a '79 Special. The fork sliders are different, but the tubes are exactly the same as the RH's. Any model Special have the same tubes so they can be had reasonably cheaply from the states. XJ 1100 forks are exactly the same as the RH, even the slider, though these are pretty thin on the ground even over there. You may even get a seller to remove the sliders to help save a bit of the postage cost, or get the whole thing sent over here then flog off the sliders to recoup some cost.
Here's some others that are a bit cheaper. Not as clean, but the seller states they're straight and have no rust
Just another option