AeroSpark
Like you when I watch from the M25 car park the 27 take-offs on the left turn to Detling do appear low but maybe it's because the turn starts very early which enhances the low altitude impression and of course many modern "heavies" use de-rated power for take-off on such long runway lengths so they will be low anyway, I remember living in Egham area in the early 70's and to watch and listen to Cyprus Airways and BEA Trident 2's on the Dover departure off 27's (28's then) to Greece and Cyprus was ear splitting to say the least but exciting all the same,