Hello 2close
If your not able to source any freebies from someone you could try an aircraft salvage company such as air salvage international (ASI) based at cotswold airport. Their website is
Aircraft salvage, recovery and disposal services - Air Salvage International and contact number +44 (0)1285 771363.
Are the mode selector switches beyond repair as that would probably be your cheapest option? Failing that....check Ebay
ZESA