You can do that but its a pretty minimal difference to picking london from the list - As you are only using solar system align ( if you can see venus at the moment) it really matters very little - get out there girl!
It will have set by the time you get back
I'll have a think about what else you can look at - might be a good idea to do it properly then and do a 3 star align.
not sure how long you will have cloudless skies for but the objects I'd get it to look for are
M31 - andromeda galaxy ( will look like a milky smudge)
M45 The Pliedes
M42 if you can see orion but not if you cant
NGC884 one of the double cluster in perseus
waaaaaaahhhhhhhh it's now cloudy!! i saw a bunch of stars
when i got back the telescope wasn't on the drive, apparently nothing could be seen because of the light, so we trapsed to the field.............still couldn't see anything- i hadn't even had a look in..........i said ' have you got the eyepiece in there?' doh so off trapsed jon to get the eyepiece i just wanted to look at venus but no we had to set it up properly, by the time it got to looking at venus it had clouded over that part of the sky
i need to read the instruction manual i think!