When you say a 2-part starter, do you mean two separate 700ml starters, or one 700 ml starter decanted and charged with another 700 ml of wort?
My sources (a brewer I trust pretty well) tell me that for starters under optimum conditions, the yeast cell volume will be in the neighborhood of 10-15MM cells per (ml *P) of 1.040 wort, which is 100 to 150 X 10^6 cells per ml of starter, regardless of original cell concentration.
Other sources (Jamil Z's website, and Palmer) state the optimum pitch rate for an ale to be around 1MM cells / (ml *P)
Assuming you have 5 gal (19000 ml) of wort at 22 *P, you need:
19000 ml * 1MM * 22*P = about 4.2 X 10^11 cells.
for optimum 1.040 starter, you'd need 4.2 X 10^11 / 150 X 10^6 ml of starter volume, which is 2800 ml of starter, or 2.8l.
Since you made 1.4l of starter, you're underpitching by about 50% (assuming two separate 700ml starters). If you decanted a 700 ml starter and added another 700ml of wort, you probably didn't increase the cell count much, and therefore only pitched about 25% of the optimum cell count. While not awfully low, either condition is low enough to expect more lag than normal. You'll probably be fine once things take off. I wouldn't even start worrying until 72 hours after pitching.