Hello, I hope the following assists you.There are a few problems that can give the concern you describe.
Ideally when the fuel filter was replaced the quality of the fuel in the filter should have been checked mainly for any sign of metallic particles that would indicate a fuel pump failing. It's quite common for the rollers inside the fuel pump to start to break up, if this happens the swarf from the pump enters the injectors causing a massive loss of power. Drain the fuel filter into a clean jar and allow the fuel to settle so you can check this.
It is also worth checking the engine management (PCM) for any stored fault codes, some codes if detected by the PCM will leave the van in limited operating mode which limits the speed to 62 MPH, any garage can do this or if you want to do it on a DIY basis a cheap scan tool can be bought for around £50 on the internet, if you do this then if possible get a tool that can read live data this way you can check the accelerator pedal is operating correctly. It may be that any codes stored just need deleting to allow the PCM to revert to normal operating.
The EGR valve can cause problems if it doesn't seal correctly, you can check this by removing it and putting WD 40 on the seat if it leaks through then the valve will need replacing.
Check that all the turbo pipe work and intercooler is OK (if fitted) and that there is a good airflow through the intercooler as I've seen quite a few blocked by debris, again if you have a live data reader check the turbo boost to make sure the turbo operates as it should.
Start with these checks, let me know if you have further questions regarding this and I'll reply as soon as I'm able to.