You can marry a non-Catholic (or even an unbaptised person) with dispensation, which is basically an exception from the general rule that you can't, but dispensations aren't normally withheld regardless. However, a non-Catholic is likely not to believe the same as we do about marriage, which is to say especially that marriage is for life (not for as long as it works or as long as the couple are in love), that marriage is to be open to children (i.e. no contraception), and that there's no cheating no matter what (this one should be easier for most people to accept in theory, but the implications are far stronger for us). If someone reserves for himself the right to seek divorce, get a lover, have no children, then one can't even validly marry. And who wants an invalid marriage? This is the practical reason why I'm sticking with Catholics as far as women go, although I don't rule out marrying a non-Catholic whose beliefs are compatible or "dating" a person who shows some willingness to learn more and possibly verify her beliefs. By the way, being nominally Catholic doesn't guarantee not believing in divorce or contraception. Also, we need to bring up our children as Catholics and that's not something that sit well with everybody. Suddenly, people may decide they don't want their children go to Confession or have to fast or abstain. Lots of people believe in allowing the children to choose, bringing them up in two religions at once or "generic" Christianity. We don't want that.
Also, I can tell you from experience that sharing a relationship with someone who has very bizarre beliefs on things can be quite taxing. I would normally avoid people who are in sects, neo-pagan groups and other artificial religions or "religions". Among us Christians, some Protestant beliefs and outlooks can be hard to deal with.
As for women your age, they're probably more likely to attend university churches, churches where there are some group activities, ministries, dedicated pastoral efforts (e.g. academic ministries) and so on. Then there are exchange students and temporary workers from Catholic countries in Europe. Besides, as far as I know, the Catholic Church is en route to becoming the biggest Christian denomination in England once again, so... :D And there are parts of England where the local populace never really accepted Anglicanism, such as some parts of East Anglia, Lancashire or Yorkshire. And then you have folks with Gaelic or Irish ancestry. There's at least more probability of finding a Catholic eligible spinster there, I guess.