No too sure that would be the case there 'Darty' as there's plenty of concrete of the same vintage that's still in use.
I recall many years in another life that there's quite a water table running beneath Tulla drome & that coupled with oil/fuel that's in the water table meant that the hydrant pipes where needing a serious look at in the not to distant future as well as the whole apron area.
Could get exy in the years to come.
Also when Tulla was designed re the A/C parking bays it was to suit 707's & DC8 sized machines not the Jumbo's of 2day meaning the hydrant spacing as well as the terminal spacing wasn't in alignment, took many years of mods & some hydrant pits being unusable.
Anyway at the rate the Drome works get done there (the current apron/taxi-way works on Alpha a prime Eg, 100 yrs in the making!
)they would have invented a diff type of flying machine doing away with the joint anyway!
The tunnels underneath Tulla are very interesting too:-) Rats as big as some CEO's
Ah the good 'ole days where you could wander round the old Wombat machines down on the freight terminal & no one would bother you as the safety officers of the day where off playing cards somewhere
Wmk2