Spooge went a bit awry....
well i've tried to seal the cabinets as best i could - only around the edges that are to the outside - if ye see what i mean. i used soem crack sealant i got from focus but being the diy duffer that i am it just went mental coming out of the can. i've tidied it up as best i can but it's a bit on the messy side however you won;t see it and it should do the job.
i've also added the bracing between the front / tl / back parts - there is an additional brace between the top / tl but that goes in once everything is lined and i think is more to hold the long hair wool in place behing the bass driver. the bracing i suspect is just a bonus.
some pics...

and...

to answer your question gtm. there are some t-nuts and bolts supplied to hold the drivers in place with. these are the ones that grip into the mdf. i believe you drill a hole first (marked up from the drivers) and then just bolt the things together after gently tapping them into place - iguess i'll be doing that before the final side is glued on too. the instructions are a bit light on info for that bit though so i guess i'll just have to wing it.
goomer - thanks for the encouragement - any and all is gratefully recieved.
tomorrow is tl lining day i guess once more unto the breach dear friends.....
cheers
julian