You can also use your VSIB embossing stamp, and use your VSIB accreditation number too!!!!
NO fitter is going to warrant a alarm that he did not supply, so if/when it goes wrong you then have to pay removal costs and reinstall costs.
This is going to cost you the best part of £200, for £250 you could leave all the hassle to someone else.
If your insurers want it CAT 1, it must be VSIB accredited which means you cannot do DIY filling in, unless you are VSIB approved, which is what they are after, but then you would not be asking on here.
tabetha