Maybe a little late to the discussion here, but I'd definitely go for the fuel filter first (especially if you're able to fit it yourself) as the part is quite cheap and can make a lot of difference on the i-CTDI engines.
The genuine Honda filter is a Bosch branded one. A few years ago I let my filter go a little over the recommended millage limit due to being broke that month (like most these days), it then started loosing power when accelerating and occasionally putting the car in 'limp home mode' which was a right pain in the **** when I attempted to overtake a motorhome on the M26, overdid the fuel filter and ended up in 'limp home mode', ended up in a neck to neck drag race with the motorhome, neither of us were able to go over 40 MPH.
Luckily I keep an OBD scanner in the car so managed to pull up and re-set it for the rest of the journey :unsure: