i need to get my 1.5 mile run from 9 50 to 8 50 for the royal marines test

the test has you running 1.5 miles in a group running it in 12.30(iv been told the pti usualy does it in 10.30 depending on his mood) with 1 min rest then a best effort 1.5mile as iv said above i am currently running in around 9.50-10.10 but need to get it down to 8.50 or lower by 8th may

i do 2 tabata sesions with 1 min rest inbetween barfoot on monday
2 45 min bodyweight sessions a week and walk barfoot across the countryside everyday for about an hour
iv just started doing this a also do full body isometrics 6 days a week every morning for about 40 mins

was thinking of adding in 1 sprint pyramid ie 30 sec sprint 30 sec rest 1 min sprint 1 min rest 2min,3min,4min an back down
and a 20 min tempo session
but if anyone has better suggestion i would apretiate it alot wether thats just staying as i am or adding in more as long as i get sub 8.50 i dont mine preferably i wanna stay as primal as possible

cheers for your help

future bootneck :]