I've just changed the pre filters,and resin,the readings are worse than before the change.
Before resin the reading is 009,after resin its 008. I flushed through fro about 2 hours with the resin inlet disconnected.
  is this configuration in the pic correct? I know its different from the original,but Doug Atkinson told me to plumb it this way to allow more pressure through the system
 Is the flush valve in the correct position? please advise.

no idea about the plumbing, i can't make the pic out on this thing.
have you made sure the housing is tight on the resin? if not tight enough you can get infiltration of the water not really having gone through di, as the readings is about the same as the ro makes it sound plausible to me

woooo          it looks like a spegetti junction    you may have to get in touch with who you bought it off and they may have a diagram

it seems i was right. that's all that matters

i've done the 2 washers as well, also don't get the flush aspect, on the surface does'nt seem logical, it just works.
i don't think filters alter tds much, unless you replace severely old with new, just protect membranes

cheers lads,you've put my mind easier now