Thanks for everyones welcoming comments.
Okey doke. Here's my conundrum. There is no right answer, simply the lesser of two evils (or three actually).
At the moment, I have an MV engine in the Doka with all the DJ ancilliaries on it. It behaved really well dring the 110 miles home yesterday, although not returning fantastic economy (guess around 20-22mpg). But thats probably the AWD talking. I also got the old DJ block with the Doka, which was a Volkspares special (see Ghia's brick yard thread), which was taken out due to a 'top end knock' which was not confirmed, simply swapped with the MV for expediancy. I have the EJ25 in the Multivan and everything is copacetic. My Dads engine and 5 speed trans has definitely seen better days but both work.
The grand plan before entry of Syncro was to upgrade the Multivan to an SVX, and put the whole EJ25 gear in my dads (thus converting it to a practical Auto for me ol' dad). But now I dont know what to do; I still have a complete SVX sitting on the drive, and it runs really well. Totally possible to sell on, although I cant see me
not putting it in something as I have already invested in a few conversion bits from the states, one of which was an Audi 200 turbo transmission from German Transaxle in Oregon.
A few people have already said not to convert the Doka to tdi and leave it as petrol to keep the Tristar as original as possible. This could lend itself to putting the SVX in the Doka, as I want it to remain LEZ compliant. But the game plan was really to have the Multivan built as the motorway cruiser, and the Doka as the fun torqy play thing.
So options are:
1.Forget the SVX. Leave Multivan as is. fix up dads engine and trans. Run the Doka as is until something breaks. Spend money on doing up Doka's other bits.
2. SVX in Multivan, EJ25 in dads velle, leave Doka as is, and upgrade to Tdi when something goes bang.
3. SVX in the Doka, leave Multivan as is, fix up the DJ and put in dads van.
I think the least disrupting option.
4. Fix up the DJ now and swap engines over in the Doka. SVX in MV and EJ25 in dads vella.
I gotta be honest, I dont want a wasser in any of them. I've read and experianced nothing but problems with them since I was about 7 when the head bolts went on dads vella on our first day on holiday

. As such, I havent got the motivation to fix up any of the wassers, which makes the tdi option for the Doka really really appealing.
Does anyone have a rear Syncro badge? Mine is missing

(Should it have one on the front too?)