i had a petrol freelander, there's no way i would have towed with it as there wasn't any 'oomph' at the best of times! since i got rid of it i've heard nothing but bad things about them.
i'm not a mechanic or anything like that but just from my own personal experience of driving one i wouldn't tow with it.
i have a freelander td4 which is 2 litre and i would only tow in an emergency as i dont think they are powerful enough. i would check with landrover for the max towing weight as i think it would need to be a small horse(as you have said) and a lightweight trailer.
I had one of the old freelanders (not the 2) and towed one horse in ifor 505 with it - was just careful - it was fine but did get sticky on grass and once had to stop for loose dog on gravelly hill and had to let it roll back to get going again - towed to fun rides, lessons. We also towed 2 horses in it as a one off when we needed to move them - we were slightly over the limit so naughty but we went the long route so totally flat - stayed at 30 or less and my other half who is experienced HGV driver drove car - no problems but wouldnt do this normally (it was only about 4 miles)
Now have BMW x5 but did have jeep which towed lovely.
I've got a Freelander 2. Max towing weight is 2 tonnes.
In the snow last year/earlier this year, I managed to get everywhere I needed to, even down a steep icy hill to pick daughter up from nursery where as others parked at the top and walked down (a couple of Range Rovers and other 4 x 4's included), it's more to do with driver capability, if you can't drive in snow and ice, it doesn't matter what vehicle you're in
I would tow with mine. An Ifor 511 is around 1 tonne unladened (I think) so it would have be a right big fatty of a horse not to be able to tow. I wouldn't tow more than one horse though.