Are you sure your oven is hot enough, and does your batter sizzle when it goes into the fat? If not, they won't work properly
Guys, guys....SUCCESS! I even managed t.i.t.h !
Hope these aren’t too Brenda’s Bangers - the chipolatas were a bit incinerated looking, but tasted great. No roast potatoes, as it was just a quick lunch. The eleven year old ate it messily, and declared it the best ever.
The oven tripped twice, but finally settled at about 200, which I think was definitely the problem previously. Thanks all!