A6 gearbox control unit

I have a 2003/53 A6 with 107,000 miles on it. Absolutely perfect condition and sat nav etc. I am wanting to sell it but typically has developed a fault with multitronic gear box. Dealer says it is gearbox control unit and about £1400 to replace. I have had about the same quote to supply and fit a second hand unit.
The car drives perfectly most of the time- except it sometimes goes into safe mode where the gear icons flash and you can not select the gears manually via the paddles. However it still drives normally in auto. Anyone know any solutions or alternatively I will just sell as is, in which case does anyone know of an Audi specialist who may want it as is?

Try changing the gear box oil, ive had similar problem and changing the oil has helped but hasnt cured the full problem although mine was more tempermental than what yours sounds...
How much do you hope to sell it for without fixing the fault?

It's in really good nick otherwise and full leather, sat nav, cd multi etc. I bought it for over £7k last year, so as is want about £5800 for it.