Fuel starvation

[Mudhutter_72]

Hi everyone,
First time poster and really hope somebody can help!
My wife has a 61 plate 1.2 TDI, about a month ago she phoned me saying the car wasn't running right and sounded rough, she got it to work but on her way home the car chugged then stalled and she couldn't get it restarted, when the recovery guy came he eventually got it started after about 4 attempts and said he thought it was fuel starvation and he towed it back to our local garage. Next day the mechanic suggested it could be the in tank fuel pump or fuel filter so he changed the filter 1st as this was cheaper. This didn't fix it so the wife took it to Volkswagon who did a full diagnostic and overnight pressure test but found nothing and said best guess was either fuel pump or EGR valve but there were no warning lights showing. We then asked our local garage to fit a new in tank fuel pump, at first we thought it was fixed but the day after the car stalled at lights and took forever to get restarted and then sounded lumpy. We're reluctant to spend more money on an EGR valve as we don't know whether this will definitely fix it and will cost a fortune (we've spent £400 already, VW was free as brother in law is a salesman there!) Has anybody had similar problems and is it fixable? P.s we've also had battery and alternator checked and ok.
Thanks in advance.