(minor edits made)
In a hardware store find out the amperes rating for a new receptacle (wall plug; wall socket) that matches the power plug (cord cap). You would want to run a brand new circuit from the breaker panel with the appropriate amperes rating (thickness of wires) and the appropriate receptacle. (When you get to the UK and the cooker's plug fits the existing receptacle, then you don't need to buy anything immediately yet.)
You may not substitute a larger (17 amp) fuse than was there originally
unless you can prove that the circuit wiring and all wired in devices (receptacles, lights, fans, etc.) are designed for connecting to a circuit with that amperage.
It is possible that you will have an existing circuit that both allows 17 (or 20) amps and is permitted to have 13 amp general purpose receptacles on it. In this case you can add a 17 amp receptacle to that circuit. This depends on your local or nationwide electric code.
AFAIK the limit for a standard wall socket is 13 amps, or 20 across two sockets.
(analogy) In the U.S. 20 amp general purpose circuits accommodate both 15 amp and 20 amp receptacles and loads (lights, appliances, electronics). If a 15 amp receptacle is present on a 20 amp circuit the entire circuit must have as a minimum one duplex receptacle or two single receptacles on it
You may not cut off the plug and substitute another with a different amperes rating. But you could temporarily make an adapter cord perhaps 2 feet (0.6 m) long with a matching receptacle for the appliance and a matching plug for an existing wall receptacle. With 13 amperes available at the receptacle you could use the cooker but not all four
burners at the same time.
You may not make an adapter cord with two plugs to fit into two existing receptacles at the same time (and one receptacle for the appliance power cord).
OT: out of curiosity: Is this cooker a tank like or casserole like appliance that you put the food into, or is it more like a stove with the
burners on an upper flat surface (cooktop) for pots and pans?