IB appeal following an ESA award

I have an IB tribunal soon where the customer has since made a claim for ESA and this is actually in payment.  I would like to think that the tribunal could use the principle regarding ‘finality of decisions’ in S.17 of the SSA 1998 and just direct that arrears be paid up to the day before the ESA award but maybe this is too optimistic?  I am concerned that the tribunal may instead reinstate the IB, direct payment of arrears (offsetting against ESA already paid), and then the customer would be ‘migrated’ to face the new severe form of WCA which they might then fail.  Any thoughts regarding what the legal position is regarding this would be most welcome.

I can’t see that the tribunal can do what you suggest. There is nothing incompatible about IB and ESA, just overlapping benefits. However when your client gets converted the DWP will just adopt the existing WCA determination:

Reg 7(2) of the Migration regs:
Where P is entitled to an award of an employment and support allowance under the 2007 Act and it has been determined in respect of that entitlement that P—

(a)has limited capability for work, or.
(b)is to be treated as having limited capability for work, other than by virtue of regulation 30 of the 2008 Regulations,.
in relation to the conversion of P’s existing award, P is to be taken as having satisfied the condition set out in section 1(3)(a) of the 2007 Act (limited capability for work).

Then I suppose it’s just a question of how long he can hang on before the imaginary wheelchair / how fit is your guide dog test!

Yes, tribunals do not usually concern themselves with peripheral matters.  They usually only concern themselves with the correctness of the actual decision under appeal and generally leave the rest to the DWP unless there is an ongoing dispute which needs to be referred back, such as a calculation of a recoverable overpayment.