Filling in CGT on my tax return - please help

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Please help me understand my tax return for Capital Gains Tax, I'm baffled and the help screens don't help much.

In July 2025 I sold a rental property for 105K.
I filled in a CGT form, worked out that my 'taxable gain' was 12,354 and that I owed 2,223.72, which I paid.
Now I'm filling in my tax return for that year and it's asking slightly different questions.
Disposable proceeds - is that the gross sale price ie 105K?
Allowable costs - is that the original purchase price plus solicitors fees etc?
Total gains and losses - would that be disposable proceeds minus allowable costs?
'Total gains or losses on UK residential property reported on Capital Gains Tax UK Property Disposal returns' - is that the same as 'total gains and losses'?
Then 'Tax on UK residential property gains reported on Capital Gains Tax UK Property Disposal returns already charged' - is that the 2,223.72 tax that I've already paid?
Then they ask about carried interest which hopefully isn't relevant.
I've be grateful for some help because I don't want to get it wrong and pay too little or too much tax.
Thank you.

Oh heck what is the 'Real Time Transaction return box'

if I remember correctly, after you fill in the form within 60 days of selling the house you estimate the cgt and pay it.

then when it comes to the SA return for that year you fill in the cgt details all over again, as well as telling them what you reported and what you have already paid. If there is a difference (for example because of additional costs now included or omitted) there will be a balancing payment or credit.

as to the terms:

Disposable proceeds - yes that is how much the sale realised

Allowable costs - there are allowable costs both on purchase and on sale. In addition you may be able to claim some other costs if there are capital not income in nature eg if you extended the property. But whether any particular cost is allowable for cgt all depends on what they were . But given the sums you mention it seems unlikely.

Total gains and losses - would that be disposable proceeds minus allowable costs? No it’s (disposal proceeds plus allowable disposal costs) minus (purchase price plus purchase costs)

'Total gains or losses on UK residential property reported on Capital Gains Tax UK Property Disposal returns' - is that the same as 'total gains and losses'? No it’s the gain or loss you reported on the 60 day form

Then 'Tax on UK residential property gains reported on Capital Gains Tax UK Property Disposal returns already charged' - is that the 2,223.72 tax that I've already paid? Yes

Then they ask about carried interest which hopefully isn't relevant. No it’s not

hope that all makes sense

Just in case you're not aware, it's possible to fill in the whole form and then see their detailed calculation of the tax or refund you owe, before you submit the form. Sometimes seeing that the calculation isn't coming out the way you expect (in your case, presumably, not much CGT to pay or refund because you've paid it already) is the easiest way to catch that you must have misinterpreted a box, and then you can work backwards. Obviously you do have to end up feeling confident you've got it right! It's also possible to put a note in the Any Other Information box (I assume by X you mean ... so I entered ...) to cover yourself and make it clear to a human.

@Ridleyxf @taxReturnStuff Thank you thank you thank you for your help. I wish I could buy you an appreciative glass of wine. The figures are in the right boxes now and a horrible task is over. x