Here are the links to some of the products and practitioners I may recommend.
Seat balance cushions for increased proprioception whilst sitting: Please search on Amazon or Google for: Togu Dynair Cushions. They usually retail for between £20-£30.
Orthopaedic pillows: On average we spend one third of our lives sleeping so an orthopaedic pillow is a wise investment. They support the neck’s natural curve, whether you sleep on your side or back.There is not one brand I specifically recommend. Pillows and mattreses are a very subjective field depending on of you prefer a very firm or slightly softer feel. However, I do recommend choosing a pillow that has a curved/contoured shape. Here are some brands you may want to look at: Harley, Sealy, Tempur. London Pillow Company.
Infant probiotics for a wide range of intestinal flora (finish one course before changing to a different brand): Biokult, Biogaia, Biocare, Dr Udos
Over the counter Orthotics:
If I have recommended seeing a podatrist please see the link below for Gaitlab, however these are a good over the counter orthotic: Superfeet insoles