British Gas and Gas Safety Check Certificate

[alenuk]

I need to do gas safety check and was bit of searching on google to find some good one and reasonable priced(agency wants 115 plus vat)
I see that British Gas are doing some
http://www.britishgas.co.uk/products-and-services/maintenance-and-repair/landlord-services/fewer-than-10-properties.html

and was wondering is it worth paying like £ 19 a months for their services or is it cheaper to get someone else .

Does anyone have any experience with British Gas and is it good?

Thanks a lot!