You can't have your cake and eat it mate. If you are getting him to put things in writing that you own this, or own that, or are entitled to this or that, it can work against you too asit is documentary proof your are using to get money out of him. Just be very careful. If you are getting a good deal on the pay off, then trying to shaft him afterwards will invariable get you burnt one way or the other. For instance, who would want to work with you when you didn't run your company correctly and then shafted your mate after he bought you out. For another instance, If you know about the PAYE thing, you are guilty by association as you should've reported/corrected the situation. Just remember, you now have this topic lodged in google cache for ever, admiting that you know of wrongful doings....