Your washing could have been "better" in pure terms, but this is very usable yeast with tons of viable cells. The downside to washing is you lose cells. Porters are neither high gravity nor highly hopped and if you diluted the beer with water, the acidity is bound to not be very low either. You do have some grub in there, but it won't affect a future beer's flavor profile. If you want it to look like some of the other examples you have been shown, pour off the dark beer/water and rinse again. You will lose more yeast this way, but it will look "like its supposed to." Some will tell you your washed yeast is unacceptable. I can tell you from experience it's viable and just fine as is. RDWHAHB