Stephen, the UK deer population is having a tremendously detrimental impact on our native woodlands, aside from climate change, over grazing by deer which suppresses natural regeneration and strips out the understorey is the probably the greatest threat to our native woodlands.
When you state 'wide open space' what do you mean? As 'ambush' predators Lynx live and hunt in dense woodland areas and shy away from open spaces because they are not equipped to hunt in them. If you mean that there is not enough space in the UK then look at what's happening in Europe where they appear to have spread into parts of Belgium and Holland from Germany.
Apart from the Scotland, the area around Kielder (densely wooded, remote, large deer population) looks ideal for the trial. We spend 10's of millions restocking woodlands and putting up deer fencing in the UK - what if Lynx can help restore some of the natural balance? It's often suggested that Lynx will start predating sheep - that might be the case in wooded areas (where sheep should really be fenced out) but it is thought the likelihood of that happening (judging by what happens elsewhere) is low. But if it was found to happen then it would be easy enough to set up a compensation scheme for farmers in a similar way to some of the sea eagle schemes in Western Scotland. Sheep farming in the uplands is largely uneconomic anyway, nearly all upland sheep farmers lose money on keeping sheep, it's only the subsidy payments that keep them so that the economic impact of predation is likely to be very low in the grand scheme of things - certainly not compatible with the economic impact of deer browsing in woodlands. Should sheep farming have such hegemony over UK land use that we can't even consider a *trialled* reintroduction of a native predator?