Put quinoa/maize couscous in a large heatproof bowl, pour over stock, then cover with cling film for 5 mins until liquid is absorbed. Combine chives, pine nuts, orange segments and herbs with quinoa. Add a good squeeze of lemon juice, season, then stir in egg. Leave to cool. (If stuffing is too ‘wet’, you can add gluten free breadcrumbs at this point)
Using the back of a knife, stretch rashers to 1½ times their original length. Lay, slightly overlapping, on a large sheet of foil to form a rectangle. Make a few slashes in the thickest part of each chicken breast and lay between 2 sheets of cling film. Use the base of a heavy pan to bash the chicken until about 1cm thick. Arrange chicken over the bacon, fitting so there are no gaps, but leave a border on longer sides. (This helps to roll up the chicken.)
Spoon stuffing over chicken in a strip along one of the longest sides. Using tin foil to help, roll bacon and chicken around stuffing like a log. Wrap tightly in foil, twisting the ends to secure, then chill for 2 hrs or up to 1 day.
Heat oven to 180C/fan 160C/gas 4. Place chicken, join-side down, in a roasting tray. Cook for 30 mins, then unwrap foil and brush roast with remaining oil. Cook, uncovered, for 20-30 mins more until cooked through, and the stuffing is hot (a metal skewer inserted into the chicken’s centre should come out hot). Cool and wrap in fresh foil to transport.