Roverdude...
A little FYI, I had that done once... once. The adapter was a special fitting for the Rover. The next time, I tried to have it done, they unfortanely misplaced the adapter and was unable to do it for me. They called the company to order another adapter... the gentleman from the company told them land Rover have not done well with the flush and advised not to do it.
Now, they either told me that because they did not want my business or they were being serious. I kind of took them at their word because if they were willing to turn away business... I was willing to belief them.
Who knows... you could be perfectly fine.