Knock the walls down including arch ways plus gates, remove offending trees / shrubs (forget trimming them - long term solution
) remove tarmac shingle the driveway problem sorted
£4500 + vat or Cash £5000 as you have asked every question so far ie Reason for problem, chemical required and now cost only other factor remaining is time 1/2 a day
Hope this helps
I think I may have sunstroke