4-person tent recommendations
I'm looking for a 4-person tramping/mountaineering style tent, i.e. not a large car-camping tent. I've looked at lots of brands (on the web) so far including Marmot, North Face, Macpac, MSR, Mountain Hardwear, Terra Nova, Exped, Big Agnes, Vango, Black Diamond, etc and thus far nothing is quite right.
The main things I'm after is actually being big enough to fit 4 sleeping mats side by side (the Macpac is not, despite being labelled a 4-person tent - I looked at one of these in person) and having a decent floor. Many/most are either not tub floors, or are only rated to 1500 or 3000mm hydrostatic head. Compare this with Macpac which is rated to 10,000.
The other nice feature (but less important) is being able to pitch the inner and fly as one, so the inner doesn't get wet if it's raining.
Can anyone suggest any other brands I should look at? Cheers...
If you're concerned about rain, go for a tent designed for Europe/UK conditions.
My top picks would be hilleberg, terra nova and lightwave (http://www.lightwave.uk.com/en/tents_overview.php).
Whatever you do - get a ground sheet. Preferably one that is designed specifically for whichever tent you decide to get.
Like you say, your biggest problem will be finding a lightweight tent big enough for four people...
My recommendation comes from experience - having used my two-person hilleberg nallo gt in very wet conditions (in the UK) and on quite rough surfaces (in the NZ bush). The groundsheet definitely keeps the tent drier and absorbs a lot of the wear that would normally affect the floor of the tent - great considering the price difference between replacing one or the other :)
I'm not sure why your tent is leaking water onto the groundsheet, though I would have to say a big difference between the tents I have recommended and the ones I haven't has to do with the design of the fly. The fly needs to have a good amount of clearance over the inner and the groundsheet, and needs to sit as close to the ground as possible to prevent water splashing up underneath. Water can and will be displaced off the ground in an upwards direction in even very light rain, and can easily jump up under a gap between the ground and the fly. The fly on my hille literally touches the ground, so no water can splash up inside.
The con is reduced ventilation, which is why it is hard to find a tent that performs very well in all climates. It is essential to learn how to properly ventilate whatever tent you buy so condensation doesn't become a problem.
My 2 cents worth... Have been using Hilleberg for quite a long time now, I have a couple, Nammatj 3GT and Akto, I got mine on Ebay, slightly (once) used and had a friend reprice it and ship it from the US, cost less than NZ500 all up. It took a while to find, but man was it worth the effort! My motto is 'get the best forget the rest '! Peace of mind in a raging storm at altitude is priceless ( there's never absolute peace mind you...!) I really dont believe there is anything as good in tunnel style tents. I am using plain building wrap to protect the bathtub form punctures, cut it so it overlaps into the vestuble, much less condensation inside that way, Hilleberg are made to operate in winds, and are very dry as long ast you open up the vents enough. No wind and they can be wet, but then you can always open the doors. These tents have a system that drags the fly to the ground using tension on the tent itself, not a peg. They are very ground hugging...excellent workmanship! Tough... Light. Roomy too.

Hilleberg.com