Yay!
It was bound to be hotter than 32.9 somewhere near the border
Carlisle got up to 34.4 (nd might have been higher in-between the hours) and I know the weather station used there is at the ex-RAF facility in the north of the city only 5-6 miles from Gretna across a flat plain near sea-level as the crow flies, so I reckon Gretna would have recorded the same figure +-1C
https://goo.gl/maps/keeiD2uwCuiybA28
Carlisle used to belong to Scotland so we can just claim it directly too
Another thing to consider is that the quoted temperature of 34.8°C at Charterhall is probably only the highest hourly reading for that station which helps to explain why it is only provisional just now.
It is only when the 18z SYNOP data comes in that we will know what today's actual maximum temperature was there and that applies elsewhere in the UK as well including those stations where the temperature has gone above 40°C.
This means that any record which has already been provisionally announced is likely to be officially declared with even higher values being confirmed for those records.
For here in Scotland, this means that we can't rule out the possibility of the new record actually being over 35°C once those actual maximum temperatures are known.
The north of Edinburgh, usually always missing out on snow events which occur not just within the rest of Scotland or the UK, but also within the rest of Edinburgh.