Well, let's have a closer look at this.
There are 2 ways to arrange 3 identical ligands in an octahedral complex. They are called mer (meridional) and fac (facial). See diagram below.
To a first approximation (assuming the 3 other ligands are the same), the 3 P atoms in the fac isomer are equivalent. If the other ligands are all different, the P atoms won't be exactly equivalent, but I'd expect them to have fairly similar chemical shifts. (Correct me if I'm wrong, nmr experts.) In the mer isomer, the 2 P atoms trans to each other are equivalent, but the third is different, so I would expect 2 signals at rather different chemical shifts. That looks like what we have in the 31P spectrum.
If you add a hydrogen, you will see that in the fac isomer it must be trans to one of the Ps and cis to the other two, giving rise to a doublet of triplets, as you observe in the 1H spectrum. For the mer isomer, there are two possibilities. In one, the H is also trans to one P and cis to the other two. In the other, the H is cis to all 3, though they are not equivalent, so rather than a quartet you would get a doublet of triplets, with a smaller doublet coupling than in the trans case, so that it might approximate to a quartet.
Taking all this together would suggest that you have the mer isomer with the H trans to the unique P.