I bought my F back in June, with about 44k on the clock. Within a month a noticed some oddities with the steering, The symptoms only showed on the motorway and were particularly noticeable in marginal conditions e.g. windy days.
You can read up on the full symptoms on the US forum via this link, but in short when making lane changes the steering could exhibit a notchy feeling, exactly as described in L-SB-0016-11.
I picked up the car from the dealer this morning. The good news is that it looks like the issue has been fixed. The bad news, £3.5K for a new steering rack. Thank you Lexus warranty!
I thought I'd share this with you all just in case you come across the issue in the future!