Dear Suzanne,
Thank you for your reply.
All of Delia’s recipes that require an oven have been tested using conventional heat.
This is because the results across gas and electric ovens using a conventional heat setting have proved to be consistent.
We do not test using fan ovens as these results vary too much.
We offer this link below all our online oven temperatures.
https://www.deliaonline.com/information-centre/oven-temperatures-and-conversions
Kind regards
Lindsey