Occupational Health form? -UK

Hi,

I recently got an offer from a big BB in London and as part of their on-boarding procedure I have to fill out an occupational health form. It states it is designed to be reviewed by the occupational health service within the firm to give the firm advice on any adjustments that might need to be made. It also asks for disabilities.

I have a mild form of Asperger Syndrome which is classified as a disability in the UK. So I am obviously aware of this condition and the form looks like I should tick the box. However, I am concerned that as I am only on-boarding now (going to pre-employment checks etc. so have not started work) this might make my offer fall though or they could change their mind to employ me? Could this happen? I generally do not feel very affected by the condition except for sometimes coming across as socially awkward.

Thanks!