Depends on the power requirements of old vs new.
If they're the same then probably DIY.
If the new one is higher then it may need a 32A circuit for example, which may be new wiring from the consumer unit, and likely a sparkie.
Edit: beaten by Airhead, and I'll always defer to him on this stuff :D
Swapping an electric hob from solid plate to induction -diy or a sparkie?