The installer could write out a Gas safety Certificate on the spot if it was part of the agreement and price.
Or he could voluntarily notify the installation to Building Control via one of the Notification bodies and they would send you a Certificate but this costs extra and as stated its not required any more.
Gas safe Register dont' want to know about cooking appliances so you won't get a certificate, they are only interested in notifing under Blg regs partL1 get your installer to fill out a home owner gas safety certificate if you want one shouldn't be a problem as he will already have done all the required checks?
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