Filling in the tax return

In my own case I just write them a letter detailing all my items taxed and non taxed. Mostly they adjust my tax on a returning P800 but this year my tax was less than a nominal amount so they made no adjustments. In fact I think I was £10 down on the deal. 

So in my case they accept my letter after they already have most of the info, pension received with tax paid. Mostly its investments and details of all my bank accounts. The main unpaid part has been P2P investments and shares investments etc. This year however with the changes to dividend tax rules and also my redirection of my investments into ISA the amounts are dwindling. I usually inform HMRC of most changes during the year using their website to make declarations. It corrects tax payments through the year much quicker.

Mrs AJU though has similar setup with a pension but has no tax liability, she claims back incorrect tax payments using the HMRC website (the old form is now online). When she first retired we used the same method as myself but as hers was a lot simpler they refused the letter method and forced the overpaid tax claim form approach. 

Not much help but gives another perspective on working with HMRC.

Next years for me should be a simpler case as my tax should not need to be altered, however as it takes very little to work out the items and provide the info by letter, rather than a full blown return I shall offer it up and see what they say.

P2P income goes under other income -OEICS, gilts etc. First box that's comes up when you get to that section IIRC. You enter the net figure of interest - capital losses being claimed + any previously claimed losses that have been recovered. Yes you can add notes to the form but it is not required. Just make sure you have your own records in case of query

moonraker. Just had chance to look at SA form & I'm pretty sure the form you quoted isn't the correct page. When you go to the other income section there should be a set of boxes listing different types of income & you select the ones you have. For P2P income tick the top box (interest from gilt edge securities ...) that will then bring up the relevant page where you can enter the amount before tax (interest -capital gains+ recoveries from previous claims) in the bottom box (UK platforms only - euro go elsewhere I think) Help sheet is here (only place P2P entry is mentioned) assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/795245/Additional_information_notes__2019_.pdf

To be fair to HMRC it is stated on the HMRC peer to peer guidance page www.gov.uk/guidance/peer-to-peer-lending

Do you have other P2P interest you could set the losses against?  See the PDF link from www.gov.uk/government/publications/income-tax-relief-for-irrecoverable-peer-to-peer-loans-final-guidance

First confirm Bondmason is eligible for loss relief as they are recievables not P2P loans so probably dont count under SAIM 12000 criteria - probably need to be entered elsewhere. If you are negative after Lendy (BM if eligible) then I dont think you need to enter anything but I would put a note stating that your interest minus loss relief is zero and you will be carrying forward relief. Alternatively, just claim loans to take income to zero and forego the rest. ( It is unclear at what point you have to claim loans but in theory if you dont claim under 'treatable' criteria then they will be subsequently eligible when Lendy define them as having 'become' irrecoverable somewhere down the line). Usual caveats apply - not advice, seek advice etc.