spx.. You really do need a sharp blade and a saw that's in good condition to avoid chipping.
So lets assume you have not got any of the right tools.
You mentioned hiring a jig and router which now seems one course of action, the problem with that is they are designed to cut a mitred joint and you want a straight joint, you can get around this by using a 75mm spacer between the location pegs and the edge of the worktop and it gives the bonus of being able to cut the bolt recesses. If you go for this do not forget you need 2 decent clamps.
Second option get yourself a circular saw, you can pick them up fairly cheap, problem is supplied blade may not be up to much. Still leaves the problem of the bolt recesses, which you can sort out (ish)with your router.
Third option get a bigger router, saw one in B&Q yesterday, £40 plus a cutter at £17. It would be a good tool to have in your kit anyway.
Make enquiries about getting a cutter for your router, please do not take my word that they are not available but as a word of caution holding a large cutter on a small shank seems a bit iffy to me.
I'm affaid it's the old story the right tools for the job, I did exactly what you want to do last Monday, I obviously have the right tools took less than 10 minutes.