Error codes and engine service required message

[jimmy s]

I have a 2.0D S40 with DPF (Euro IV)
I have recently had error message engine service required message on dash when giving it some beens (3500-4000)

I have PPC code reader and codes are
ECM-242F ECM-242F Particle trap. Blocked
ECM2455 ECM-2455 pressure sensor, particle filter. Signal too high
ECM-2456 Pressure sensor, particle filter. Signal missing

It doesn't go into limp home mode yet, just error message.
It's done 175,000 so I suspect replacement DPF filter is way overdue.

I see it my options are
1 Wait until it gets totally blocked/limp home all time
2 Bite bullet and get new DPF filter anyway £200 of flea bay probably at least £450 fitted at garage.
3 Drive at 2800-3500 revs for a few days to burn it all off (what about ash?)

I do high speed 1/2 drive every day not short trips.

Will waiting do any further damage, or will I have to replace DPF at some stage anyway in which case I may as well wait. Any comments or similar experience gladly welcomed.

Jimmy S