I've broken a few gearbox mountings on my Fiesta Si, so have been looking at possible alternatives that may be a bit more robust. Didn't really want to spend £100 on a pair of Vibratechnics mounts though.
Turns out that Land Rover V8 engine mountings are a direct replacement. Same threads, and almost the same thickness (maybe a millimetre or two thinner). They also appear to be made of harder rubber than the ford part. ANR1808 is the part number.
I have fitted a pair of these, and so far they seem to be working well. They do transmit more noise and vibration - as you may expect - but movement of the engine and gearbox seems to have been reduced. Only time will tell how well they last, but they have been on the car for my last 3 motorsport events, and they seem fine.
The best part about this is the cost:
Vibratechnics mounts - £50 each.
Standard mounts (non-genuine) - £25 each.
Land Rover mounts -
£4 each (including delivery) from ebay.
Some people may already know about this, but I haven't seen it mentioned on this forum before, so thought I should post the info in case it helps anyone else out.
Some photos below:

Land Rover mounting on left, Fiesta Si mounting on right




Front of cradle

Rear of cradle

Front of gearbox

Rear of gearbox
