It is decently certain that something is reportable, although there is substantial authority to treat this in more than one way on a US income tax return. Thee are several dual US/UK qualified tax professionals in the UK. Given the risk of getting this wrong, you may wish to engage a professional just for the one year so you know exactly what the position is that produces the optimum result in your circumstances.
£1,200 is not an untypical fee for a dual US/UK qualified tax professional given the costs of paying for staff salaries, office rent, business rates, insurance and professional education in the UK.