105 units have so far been deregistered (excluding MKIIs
deregistered earlier). Regos are SBS 1696L to SBS 1800C.
If we add SBS 1805P, SBS 1815K, SBS 1824J, SBS 1836A and SBS 1867K,
that adds up to 110 units. 90 units, including those on lay up
(were their parts cannibalised?), are still not deregistered.