Yes, with a blanked EGR it will always have an insufficient flow code which will put the light on and also it will be running on default settings I think.
The only way to turn it off is to make the engine forget about the EGR using the software and then delete the code.
The IPF is about £500 though
Thinking I might have to go down the same route - I have the original spec EGR and I'm sure it's sticking at getting a flat spot at 2k. Not bothering with the new type ones cause they're rubbish so the next step is to map it out. Dear Father Christmas...