Preheat the oven to 200C/180C Fan. Line a baking sheet with kitchen paper and set aside.
Pour the oil into a large roasting tin and pop in the oven for about 5 minutes - or until it is very hot (like you would if you were making roast potatoes).
Tip the sausages into the hot oil and spread in an even layer. Pop in the oven and roast for about 20-25 minutes - or until golden brown.
Using a slotted spoon, remove the sausages from the tin and place onto the baking sheet lined with kitchen paper. This will help remove any excess oil.
Carefully discard any oil remaining in the tin. I use kitchen paper to wipe the oil out as there shouldn’t be loads left but if there is, just tip it carefully into a heatproof bowl and discard once cool.
Meanwhile, in a small bowl, mix together the honey and mustard.
Return the sausages to the tin and pour over the honey-mustard mixture. Stir well until all of the sausages are evenly coated.
Return the sausages to the oven and roast for a further 5 minutes, shaking the tin halfway through, or until the sausages are gloriously golden and sticky. Watch closely to ensure they don’t burn!
Meanwhile mix together the mayonnaise and wholegrain or Dijon mustard, to taste, in a small bowl. Set aside.
Remove the honey mustard glazed sausages from the oven and tip onto a serving plate. Serve straight away with the mustard mayonnaise.