for motorway riding, i do suggest you stay clear of 125s. the never reach a power out put of 33bhp unless you look at apprilia RS125's but i personally would advice against it.
bikes that usually are naturall 33bhp are 250cc motorcycles but these are beccoming a rareity these days.
what i suggest for a begginner bike is a Honda bros400. they are always 33bhp, and you will be able to ride one of them for 2 years no problem.
the beauty with the 33bhp rule is that you can buy any bike and restrict them to 33bhp. the bike i got now is a SUZUKI GSX600F, unresticted it's power output is about 88bhp, but i had to have it resticted to 33bhp and it's lovley
so you have plenty of options. like i say i recommend you stick, for now to restricted 400's