external door in gable end

Are there any restrictions in Building Regs and/or structurally about putting an external door into a gable end.

The cottage is single storey with attic space under 45 degree pitch, double corregated tile roof, approx 1910, red brick and each gable end contains an interior chimney stack. Very small, ex-farm worker's cottage: 4 rooms only leading off central hallway.

I have looked around locally and can't see any cottages of this style with doors in gable ends. My cottage has one small window in one end, offset, and nothing the other end.

None.

The only possibility I can think of, is the limitation on opening sizes if the wall is close than 1m to a boundary. If so, this will limit the amount of glass in any door, but its not a big issue to overcome