Replacing gas cooker on a narrowboat?

Hi... I am moderately competent at any DIY and currently refitting my narrow boat with a new (bottled) gas cooker. The old one had a piezo igniter and worked fine. The info from the installation manual for new one and problems is given here below as the message I sent to Hotpoint (and their parts department) THREE times with no helpful reply. Advice from anyone??Tony

Brand: Hotpoint

Model number: HAGL51K

Product category: Bottled gas cooker

Message: Hi. It is a few months since I downloaded the User Manual for the Hotpoint HAGL51K cooker. The sales info for this model describes it as "very suitable for a caravan or boat or where there is no regular electrical supply". I have a boat! In the manual it mentions an "The battery holder is located in the plinth panel below the oven door. Open the oven door fully. Press the tag on the left hand side of the battery holder/cover and withdraw it just enough to get access to the battery" I have spent many exciting hours looking for this with no success. Definitely NO battery hold and NO 'tag on left-hand side'!! The cooker comes with a 240v cable but no suggestion what it serves or how it would work on a boat with 12v supply. Any suggestions? PS: There is no indication of a piezzo or other igniter or oven light in the whole manual!!.