Thanks, but that still poses a problem as by rights if my opponent places TF protected baggage on their rear base line then I could quite possibly deploy my entire army 400p from it, in all likelyhood ending up behind my opponent!!! Could I then deploy facing my opponents rear?
No, come on, you're being silly. There are other rules which limit how far forward you can deploy:
The army deploying first must not deploy any elements further forward than 240p short of the battlefield centre line, or the other army any elements further forward than 400p short of the battlefield centre line, unless in a fortified BUA or in ambush.
And as for deploying facing your opponent's rear:
Elements not in ambush or in PF or TF must not deploy facing their army's base edge.
As for the gateway issue, from my reading of the rules it does appear to say TF need a gateway as mounted cannot cross apart from at a gateway? I think that perhaps Ditch and palisade might justify a gateway, but plashing and waggons do not.
I suspect its just a badly worded section that was put in to prevent players deploying their elements too close to fortifications placed around BUA that might well be in forward areas of the the table.
I know many sneaky rules lawyers who could use this to their advantage, especially in competition games!
Again, I think you're over-reading it, though I accept it's not as well written as it could be (as, for that matter, is a lot of the rule book).
Yes, mounted can't cross TF except via a gateway. That doesn't make gateways compulsory if you have TF; it just means that if you have TF without a gateway, the mounted in your army are going to have to go around it.
As for having a forward-deployed fortified BUA, you can put troops in it, but if it doesn't have a gateway, any mounted in there aren't going to have much effect on the game. I remember a guy who used the fortified-BUA-with-garrison-in-the-enemy-deployment-zone trick about ten years ago in a DBM competition. It threw a few opponents off their game, but one opponent took one look at the BUA and went straight for it. The garrison was a long way from their general, so they took a lot of PIPs to move around to counter attacks on them. And the number of elements in the garrison was enough that losing it demoralised that wing of the player's army. Defeat soon followed...
And sneaky rules lawyers aren't as serious a problem as they used to be in 7th Edition. Firstly, DBM got played so much that a lot of interpretations were developed which were accepted widely enough for umpires to enforce, and only really isolated players got caught out. Secondly, the rise of the Internet made it a lot easier to discuss problems and broadcast interpretations and explanations. After a few years of DBM, it was very hard to come up with problems which hadn't been seen before. This made it a lot easier for umpires to override players.
We haven't got to this point with DBMM yet. There's a group of players who've been working on a set of interpretations and explanations, and they're available on the main DBMM web-site. They haven't yet got Phil Barker's imprimatur, but we used them at Cancon back in January, which has been the largest DBMM competition to date.