'A bit of a run' for my car question

Due to personal circumstances, our diesel car which was previously used for long journeys now mainly does town runs. So every now and then I give it an hour run at a steady 40-60 on main roads, to give the battery a chance and burn off diesel particulates.

Other than the downside of burning a bit more fuel, do you think there’s any advantage to keeping the revs up by 500rpm, by driving in 4th gear instead of 5th? I’m thinking that the higher revs may assist particle burn and better charge the battery.