MK5 fiesta 1.25 , will be cheaper than the ka and possibly less rust issues. Tough little cars if kept maintained, and with soooooo many on the market, you will be able to pick and choose colour/condition.

If you get the right colour then after 6/12 months you could look to make it into a Zetec S rep as you may be earning a bit more and the insurance may not be too horrific - but maybe so check lol!