Another suggestion is to work out the travel schedule for the remainder of the year if possible, if you think you are short, you might want to do some mileage run now especially LHR is usually on every week's websaver, I am quite sure they will be gone when summer comes around and most likely won't be around in December as well.

Doing domestic flights for mileage run is really ineffective considering that you need to at least upgrade yourself to get more than 50% Q miles.