Any suggestions on minoxidil 5% foam dosage (Regaine product, UK)?

Used Rogaine as directed twice a day.  The exact amount depends on the area you are treating.  It may take 6 plus months to see changes.

You have said it correctlyOne half cap is maximum amount. If one has lesser degrees of hair loss (especially just corners of temples) one might use slightly less. Studies have never been done to evaluate dosing in such situations but I generally advise slightly lessMinoxidil will not help a maturing hairline as you have stated but may offer some benefit to slow or stop genetic changes

This is a good drug for growing new hair. It works on the place were you place it and it must be applied regularly, at least once a day, preferably at night. Just apply the liquid directly to the part of the scalp that you want more hair and in about 50% of people, they will see new growth in 3+ months.