Nick, don't know if you remember but you posted a message to me some time late last year RE: the sat nav error 'please insert disk , check disk'. Well I had a quote from Lexus Chester, and it came out at £1460... haha, their having a laugh. Anyway, I started investigating how I can fix it myself. You'll be pleased to know I have now fixed it and is working perfectly. All you need to do is go on to Ebay, type in Toyota Nav. This then brings up Toyota Avensis Sat Nav units... For some reason there are lots of them on there. I paif £75 inc postage as a guide. When you get the package. Open the outside case and to your surprise you will see a cd drive which is exactly the same as the good old Lexus number. It's exactly the same part. Just plug it in and away you go. I know this has been a long awaiting problem for you so hopefully you will now know where you are going. All the best
Daz