Hi,in the Hurricane pilots manual for the MK1,Merlin II engine(what we have in COD)it states under the following for 'Approach' and sub sectioned under 'Flying in poor visibility':
'When necessary to fly at low altitude it is advisable to open the cockpit hood and lower flaps fully.In this condition a speed of 80-90 m.p.h.,A.S.I,reading may be maintained with engine r.p.m,of 1,700-1,800 without vibration and with good control.In addition ,some pilots prefer to lower the undercarriage'.
Hope this helps,just about to read that book too.My user name is Plt Off JRB Meaker he was with 249 Squadron so I am interested to see if he is mentioned in it.
On the 27/9/1940 after being hit by the crossfire from a Ju88 he bailed out only to hit his tail on doing so and died of his injuries,my username is a small tribute to guys like this.