You could probably make seals, the top seals, around 1cm (maybe 2cm) thick x 9cm x 16cm rubber with a slot cut in it for the bar' foot and bolts to go through. Pingi's are little desicant pouches that you put in a car, they absorb the moisture, and you microwave them to dry them out, thse are invaluable on older cars in the winter, especially useful on our freelander.
As for the heater, I'm presuming its a TD4 engine in yours basically LR goofed on the coolant system, fortunately not in the cooking the head gaskets sort of way as they did with the 1.8, but instead in the sort of hardly any hot water goes to the heater matrix because of the way the designed the coolant system kind of way. In essence the cooler for the EGR on the engine, and the heater matrix are piped in parallel, the heater matrix has a higher resistance to flow than the EGR cooler, so hardly any water goes through it in comparison to what goes through the EGR cooler. I've removed every trace of EGR from our hippo, as in physically removed the cooler, the EGR valve, blanked all the lines and ports connected to it, thus any coolant in that section of the loop has to go to the heater, and this makes the heater a lot better. Thats a fair bit of faffing about to go to for a better heater, a simpler approach would be to make a restrictor ring as in a washer, to go inside the hose taking coolant to the EGR cooler, the smaller the hole in the washer, the more coolant it will divert to the heater, but I wouldn't blank it, from memory the coolant pipework to the EGR cooler is is around 3/4" leaving a 1/4"-3/8" hole in the restrictor ring washer should be fine and still give you a better heater.
Another potential source of poor heater performance is the engines thermostat, these fail in an open position, meaning the engine never really gets to full temperature, and that results in poorer MPG, and poor heater performance. The thermostat on the TD4 is awkward to get to, a lot of people on here have taken to inserting an inline thermostat from a renault inside the top hose, a look around this forum will find a recent thread on the topic. So with home made rubber seals, Pingi dessicant bean bags, reconfiguring the coolant pipework relating to the heater, and possibly even the inline thermostat mod as well, you should have a toasty and dry freelander.
