Diamond or carbon blade for short cut in concrete?

I'm looking to hire a Stihl saw to make a 2m long cut in concrete which is only about 75mm thick.

The carbon blades for the saw are only about £3.50 whereas the diamond blade is £30.

For such a short cut - do I really need to go for the diamond?

I'm looking to hire from here https://easytoolhire.com/north-west-england/12-cut...

Hire of a disc would seem best for your application but if that’s not an option I’d go for the diamond. Even on a 2m cut you’d likely get through 2 or 3 carbon(carbide?) discs, as even if they still cut they wear away considerably and you may not achieve your desired 75mm depth of cut.

How much is your hire charge?

I bought a large grinder and it came with a diamond blade. I think it was around £70 from B&Q.

[edit]

https://www.diy.com/departments/mac-allister-2000w...

£82 including blade

What’s your location? I’d lend you mine if you are nearby.

Fair enough, but I'm the kind of cowbow who would take the guard off and use a bigger blade

It starts to defeat the price saving though, so hiring would seem the way to go.