EPA and S.25 Trustee Act 1925

We have an EPA appointing son and daughter-in-law as attorneys, jointly and severally. Mum has lost capacity and the EPA is registered with the OPG. Son is now trying to sell the property which is registered in joint names with son.

Included in the EPA is this clause:

"I further appoint my said son xxxxx and his wife the said Xxxxx to be my attorneys for the purpose of the Trustee Act 1925 Section 25 with authority to execute or exercise on my behalf all of the trusts powers and discretions vested in me jointly with the my said son xxxx as Trustees of the said property xxxxxxxxxxxxxxx aforesaid of which he and I are the registered proprietors and to execute any Deeds or documents which may be required for that purpose.

The Power of Attorney is a Deed and has been executed by me as a Deed."

The conveyancers won’t accept the EPA as valid - they believe the clause above is a contrary intention which defeats the Trustee Delegation Act 1999.

Is a court order required to remove Mum as a trustee? I’ve never seen a clause like this in an EPA before so any assistance gratefully received.

I also have never before seen such an additional clause, and do not consider it helpful. Perhaps the conveyancers dislike the omission of any “joint and several” appointment in this part of the EPA?
However, I would argue that this part of the EPA cannot be a contrary intention to the EPA itself as (a) it is expressed to be “further” and (b) a s25 Power could only be valid for a maximum of 12 months - which has long since expired.
Clearly the OPG have accepted the EPA itself, which includes the power of attorney(s) to exercise trustee functions.
It may be that the conveyancers are also thinking of/worrying about the “two signature” rule. If so tell them that the son will sign in his capacity as trustee and the daughter-in-law will sign as attorney for Mum-in-law.