New SV650 K4/K5 Plug in alarms from suzuki....
 

anybody tried one of these yet?

http://www.suzuki-gb.co.uk/partdetai...id=100002&m=24

Thatcham 1 approved sounds good.
Is £283.00 a fair price?

George White in Slough charge £299 for fitting of a Datatool Cat 1.

Obviously that Suzuki one is self fit...

I'd check your insurance - i'm insured with AXA through Carole Nash who don't offer any discount at all on security products... So i didn't bother fitting one!

Sounds like a decent price for a Cat 1, especially a self fitting one. My Cat 2 was around £200 including fitting.

After a recent episode with my insurance company i found that fitting a Cat 1 alarm did nothing to the price of the insurance but the company would not insure for theft if the vehicle is not fitted with a thatcham approved alarm system.
It does however depend on the vehicle and company used.
I did have an alarm fitted that was equal to the spec of the new alarm that the company insisted i had fitted, it wasnt on the Thatcham approved list.
As alarm companies bring out new models and get them added to the thatcham list, it knocks an old one off the bottom, which happened to me 2 weeks after taking out my policy, it was a good deal however and was going to cost me to cancel. Coincidence?

Surely if when you take the policy out, a device is thatcham approved, they can't change your policy retroactively?

They can and they did.

What electrical difference is there between the K3 and K4 that this alarm won't work on the older bike?

Insurance companies will give anything a go once if they think they can get away with it. If questioned by a higher power the response tends to be "Oops, sorry! We'll look into it...".