Yes, she undoubtedly put in time, effort and research, but it's still a pity that they ended up with a fairly risible documentary thanks to her lip-quivering performance.
I mean, this is an amazing archaeological find of huge historical importance. But the programme was history-lite - I expected it to be at least a Time Team special, which would have had some proper, enthusiastic but professional experts to explain it all.
Instead we got someone who 'knew' where the grave was because she got shivers down her spine when she walked over it. Which must have been pretty galling for all the dedicated archaeologists who have degrees, who've slaved on digs in all weathers for years, and have devoted their lives to their jobs. I don't suppose they feel any less 'passionate' about their discipline than Philippa L does; they just go about it in a more controlled way!
Also, given the number of experts who get roped in on Time Team, I suspect that the pinpointing of the grave site was rather less Philippa's sole discovery than the prog let on. I bet there was far more research from many more people before they got to the point of actually starting - but again, the prog glossed over all those minor details 
Having said all which, I still watched it to the end gritting my teeth whenever PL came on