Tumble dryer wall ventilation done entirely from inside

I installed a third floor vent from inside , drilled small hols thru below proposed hole and passed a line thru , dropped to floor and tied on square sided bucket and then pulled up and tied off under hole, drilled hole and caught debri in bucket , dropped another line thru hole and tied on vent and pulled back to hole, squirt of silicon thru hole onto ext vent cover and pulled into place and tied off till set then installed fan [in your case vent.]

 

I go back to my comment made back in May. This is an 'effin' wind up. A long & boring one too!!!!

 

Possibly - but worth it for Nigel's technique!