I'm still looking for the master cylinder. Lexus will sell me a complete assembly for nearly £1990, although they will offer the two components separately - £1346 for the master cylinder and £1100 for the brake booster. I guess from noise we need the brake booster part ?
I have disconnected the plug like 'pb32' to stop the noise and warning signal and have lost abs and traction control but I managed without them in the Jag.
I'm not paying full price unless I have to so I'm looking around for a used part or maybe importing from the States if I can find someone.
I have emailed Aisin but had no response (I think the email went to Belgium) so I going to ring their UK office tomorrow.
My car has done 130k btw