Seniority
Back in 1918 the old RNAS squadrons were reallocated 200-series numbers, eg 1Sqdn RNAS became 201 Squadron RAF. Squadrons in the 2xx range have traditionally been Coastal or Bomber (ex-Handley Page 0/400) Units. So 216 Sqdn does have a fair bit of seniority and with the Bucc the maritime connection was retained.