Remix
The first issue to consider is your age, once you reach 65 or State Retirement Age, whichever is the higher then you cannot receive the Mobility element if it is not already in payment, even if you meet the criteria for an award.
Answering several of your questions in one, there is no point you taking any further action unless you are going to challenge the award for the Mobility component with an expectation of scoring at least eight points! The only mechanism for your concerns to be dealt with is an MR.
There is the potential for a knock-on effect to your ESA but if this were to happen then I think it far more likely that this would occur a future review rather than it initiating a reassessment now, meaning that you could deal with it at that time rather than now.
If you have not already done so, I would ask for a copy of the assessment report by contacting the DWP office dealing with your claim, this should give you a better understanding of how the Decision was made.
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
