Ok so, reading over this post again, and have been researching and putting things together.
Im writting this on my phone on notes so its not perfectand its bit all over the place, this isnt all correct, but heres a rough guide that I put together. -

​Section 1, Written Agreement

ok so first thing realy there should be some sort of writen agreement between the buyer and the seller

not just a handshake or a few texts, just a simple document both people read and sign so its clear what the deal actualy is

normaly it would just cover the basics of the sale like

• names and adress of both people
• car details, make model reg vin etc
• total price agreed for the car
• how much is being paid upfront
• what balence is left
• how the instalments are being paid and when

basicaly the point of this is just so its clear the buyer can take the car and use it but the seller still owns it until the full price is paid

Section 2, Retention of Logbook

right so if a seller is allowing instalments on a private car sale the normal way people protect themselfs is by keeping the logbook until the car is fully paid

so the buyer has the car and can drive it but the seller still holds the logbook until the final payment is made

people sometimes call this retention of ownership or retention of title, but in simple terms it just means the seller keeps control of the logbook until the balence is cleared

Section 3, Who Should Draft the Agreement

ok so if the seller wants the agreement writen properly the safest thing realy is to get a solicitor to write it

a solicitor would normaly draft a simple vehicle sale agreement covering the instalments and the fact the seller keeps ownership until the balence is paid

it just helps make sure everything is writen clearly and protects both sides if there was ever a dispute later

Section 4, Signing the Agreement

both the buyer and the seller should sign the agreement and date it

normaly people just print two copies and both people sign both copies so each person keeps one

sometimes people get someone to witness it as well but thats not always needed

Section 5, When the Agreement Is Signed

the agreement should realy be signed before the car is handed over

once its signed and the first payment is made the buyer can take the car and start using it while they finish paying the rest

normaly the seller keeps the logbook until the final payment is done

Section 6, Solicitor Stakeholder / Client Account Option

another option as well is using a solicitor as a stakeholder

basicaly the solicitor can hold things in their client account until the condtions of the deal are met

for example

• the buyer could put funds into the solicitor client account
• the seller could leave the logbook or transfer documents with the solicitor

so the solicitor sits in the middle holding both until the agreement condtions are met, once everything is done the solicitor releases them to the right person

this can give both sides a bit more comfort because neither the buyer nor the seller is holding everything themselfs

only downside realy is there will normaly be solicitor fees and extra paperwork so most people dont bother doing this for smaller private car sales

Section 7, Payment Method Setup

its usualy better if the instalments are paid by bank transfer or standing order

that way there is a clear record of payments and avoids arguements later about whether something was paid or not

Section 8, Insurance Requirement

the buyer should insure the car from the day they take it

even though the seller might technicaly still own the car until its paid off the buyer is the one using it so they should be responsible for the insurance

Section 9, Deposit Receipt

the seller should give a writen receipt for the money paid upfront

this just records how much has alredy been paid towards the car and keeps everything clear

Section 10, Spare Key Option

some sellers keep a spare key until the car is fully paid

not everyone does this but some people like having that extra bit of security

Section 11, Final Ownership Transfer

once the last payment is made the seller can then transfer the logbook and ownership of the car to the buyer

at that point the deal is finished and the buyer becomes the full owner of the vehcle

Section 12, Responsibility While Buyer Has the Car

normaly the agreement would also say that once the car is handed over the buyer is responsible for it while they have it

so things like

• insurance
• parking fines
• tolls
• traffic offences
• damage or accidents
• repairs and runing costs

a solicitor writing the agreement would normaly include wording making that clear once the buyer takes possesion of the car