[snapdragon]

I also had a bad experience with mackies, but it was around 2003-4, so probably doesn't count. There was nothing wrong with the gearbox in my Omega, but a couple of us from the owners forum went there and met up to have the gearbox filters and fluid changed.
They charged me for some 'magic potion' to be added, and this was never asked for nor authorised and in fact I only went there because they said they would use Texamatic 7045 rather than some universal stuff elsewhere then they probably changed the properties of this with some potion anyway because the shifts were perfect before and not so great afterwards.

It also weeped around the sump gasket afterwards and dripped about one drip a day, the only reason I can think is they didn't have a new one perhaps and reused the old gasket. There was an email chain at the time and I asked for a refund but they were not apologetic or helpful. If they just knocked off the price of the potion thatw ould have been a good gesture but they just said they add it to every gearbox and never had a problem.