Bear in mind that the rail service in the the UK can vary from reasonable to Shocking, you will most likely fly into Heathrow and then id recomend you hire a car and travel north, depending on what time of day it should you around 5-6 hours to reach the border at Gretna, there are a number of service staions with holiday inns etc just over the border, or find a guest house on the net and stay over, you are now around an hour and half to 2 hours from Glasgow or Edinburgh or 3 hours or so from Stirling, maybe 6 hours from Inverness

When you get to Gretna you are within an hours drive of Pour1malts estabishment so maybe thats a good stopoff point. Im sure Robertson would have plenty of advice and where to see.

I normally make my jouneys in chunks of around 2 hours then stop for the loo and a cake, bear in mind the roads around London are very busy and people amy drive on a different side of the road from wher you are,