Ah right, well this is because this layout was based on today's LHR pattern so I could change periods and have BA airliners on it. Then I realised that R/W 27L was 28L in the '60s, so I changed the runway markings but nothing else (call it 'modellers licence. if you like). Now the 'new' layout is based on an accurate photographic image for the period so will not include Block 86. One day I might do a later version, but the '60s gives so much more variety of airliner types to portray - pistons, turboprops and early classic jets.