Migration, from ESA to UC and other benefits affecting UC. Double deductions.

Hi,
Before migration to UC in May 2025 i was on old style ESA where i qualified for both IR and CB ESA. The payment was broken down as follows.
Living expenses £92.05
Severe Disability Premium £82.90
Disability income guarantee £21.20
Support group element £48.20
Gross total Income related ESA £244.65/wk.
Minus a 20% Industrial Injuries Disablement Benefit award at £45.06/wk.
NET total ESA at £199.59/wk or a £864.89/pcm.

I was told this amount would be transitionally protected, meaning that between ESA and UC my combined payment would remain this amount for the forseeable future. Or so i thought.

When i moved to new style ESA my new payments became
Personal allowance £92.05/wk
Support group £48.50/wk
Total 140.55/wk, or £609/pcm.

My UC payment May 25 to May 26 was calculated
Standard allowance £400.14
LCWRA £423.27
Totalling 823.41

UC transitional payment was calculated in the following way.
864.89 - 823.41 = a TP of £41.48/wk to match Legacy ESA of £864.89 that was Pre migration & after IIDB deduction.

This meant my calculation for UC was
864.89
• 609 ESA
= 225.84/pcm.

There was no IIDB deduction, as it had already been deducted from my ESA award. Or so i thought
.
In may 2026 however, the way they calculated my UC changed.
My UC, new style ESA and IIDB payments all went up, meaning my transitional protection reduced from £41.48 to £10.19. I have no issue with this and understand why it occurred.

However, UC also changed my calculation and started deducting IIDB from my UC despite this deduction having already been accounted for in my initial Legacy ESA calculation.

This meant my calculation for UC is now,
864.89
- 609 ESA
-202.71 IIDB
= 29.95/pcm.

It means that my income has dropped in very real terms by £202.71 from what it was when i was on legacy ESA, which is supposed to be stable at £864.89 pcm.
Its not like IIDB is a new benefit for me, its the oldest one i have on file and all benefit types including UC were aware of it.

Was transitional.protection supposed to be calculated at Gross ESA before deductions, or at net ESA after deductions?
Has transitional calculations messed up here, or is it correct that UC deducts these deductions again?
There literally is no point in me claiming IIDB anymore. I am paid 202 pcm yet am effectively being deducted 404pcm by continuing to claim. I literally done knoe if stopping my IIDB claim will reduce my calculations further making me worse off instead of cancelling this second deduction out so havent done anything yet but im really worried.
Its not just the difference between food or not each month, its the total of food,fuel for hospital appointments and my mortgage each month. I have nothing left to cut to be able to deal with this. An overpayment clawback would have to bankrupt me and see me sell the house to afford it on top.

Is this by design, so they force people off of lifetime awards to improve their statiatics, or has something gone very wrong?
I dont understand how a supposed set guaranteed amount can just be deducted for a second time. Ive spoken to two UC advisers today. One dismissed me outright saying i will be due a £2700 overpayment clawback and was not prepared to go through these calculations with me to engage in a dialogue and help figure it out. The other said its correct, yet told me i am free to complain, though it wont change a thing.

After taking the £1000 hit on migration by losing the 5 weeks payments, ive just barely paid that loan off and now see my income reduced by a further 200 quid a month, with a prospect of it getting even worsenif they try and take £2700 in overpayments off.