Too late to post it but I do like to know the answers!
27ac. Reportedly brakes in one limousine put off head of state [7]
i---p--
I haven't got 23 or 22 down, so if anyone who still has the crossword could give me those!!?
23down is 'Drop the pair appearing only at intervals'[4]-e-r tear? as in drop?
22 down 'Cut about Kew's earliest blooms'[5'
--n-s Not sure about first letter