Spot on the upper nose I assume - Location of the hole in the panel to access filler cap.
Anti slip - Yup looks weird but it's visible on the pics.
Don't think they were polished, when first introduced in 1942 they had a service ceiling of over 40,000ft, a top speed of 408mph, and a great climb at extremely high alts.
By D-Day high alt fighting had all but ended for the RAF, hence the removal of the extended wing-tips on VII's.