Oh Tracy, what did I say in my second post? Spotlights with 10 watt filament lamps will be too heavy a load and flatten your leisure battery very quickly, but you then said they were LED spots.... Since you've already bought them it's a bit late now but I'd strongly recommend that you take the filament lamps out and replace them with LED versions like this
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0173934975" onclick="window.open(this.href);return false; A fluorescent draws only slightly less current than a single spot does, but in order to achieve an equivalent brightness and spread of light in the van may take three or so spotlights being on.
As far as the fluorescent strip light is concerned, try temporarily connecting it and a suitable length of cable to your existing lighting circuit, turn all the other lights on and then give it a whirl – it'll either work or it won't ('won't' meaning the lamp doesn't strike properly and just gives out a dim or no light).. If it doesn't you'll have to run a separate feed to it. I believe this size of fluorescent draws a smidge under 1 amp.
The cable from the starter battery goes to the 'Car' side of the Zig and the cable from the leisure battery goes to 'Caravan'. BOTH of these need to be fused at 30 amps as close to each battery as possible (re-read my post about what cables to run and where).
Right then; relay.... As the old saying goes, there's more than one way to skin a cat. I have separate relays for the split charge system and the fridge fitted, but you can do both jobs with one relay provided it'll handle both – as your relay is rated at 200A I really can't see this presenting any problem. You can use a scotch block for the signal wire but if it's what I think it is, it's a 'one off' connection and you'll have to destroy it to disconnect it if you ever need to.
Looking at that split charge 'kit' you've bought it's designed to charge at 10 amps so I can't understand why they've chucked a 200A rated relay in there. 10amps quite frankly is next to useless, harking back to the good old days as I mentioned in a previous post. I don't know what size cable they've supplied but the crimp connectors are blue so for a 2.5mm cable, 28/0.3mm suggests 28 strands of 0.3mm = 8.4mm but it doesn't look that big. Has the reel got any other size description on it? Anyway, I'll assume we're sticking to the 6mm cable you've bought. You need to fix the relay to the metalwork under your front seat as close to the battery as possible - you'd be best to remove the seat while all this is going on anyway. The signal wire goes to one of the small spade type connections on the relay and a black from the other spade connection to the positive terminal or vehicle metalwork, whichever you prefer. It shouldn't make any difference which cable goes to which spade connector, but just check the relay for + and – markings just in case it's polarity sensitive.
You say you have a 4 way fuse block. What sort is it?
Next you need to run 3 x 6mm reds from the starter battery positive terminal to one of the threaded terminals on the relay., be VERY careful that you run these so as to keep them short and in such a way as to avoid any possible damage as they are not going to be fused. Be a good idea to tape these together too. The blue round open hole crimps that were supplied with this kit are too small for 6mm cables – you will have to source the yellow version of them and you will need at least nine (get a few more in case of "cock"-ups). The 2 x 6mm cables that you've run from you leisure battery (as per my previous post) need connecting to the other threaded connection on the relay, but these cables need individually fusing at 30 amps at BOTH ends and as close to the relay and leisure battery as possible.
Ideally, the 6mm to the fridge is connected to the same threaded terminal as the 6mm cables to the leisure battery but this cable should be fused at 15 or 20 amps as close to the relay as possible. The black to the fridge goes to the negative of the starter or leisure battery or van metalwork. I'm assuming all the other wiring I mentioned in my previous post has been connected – blacks, Zig etc?
Rotten old Courgette... I don't mind sharing!! 
I can understand that I need one to go to the relay and one straight to the 'Car' switch on the Zig, but the third? 
Look Tracy, if you want, why don't you get a few ice cold cans of 1664 in, a bit of cash for me petrol and I'll pop over and help you do it? My fingerprints are wearing off....... 
Easy tiger..................