Change percentage ownership of tenants in common property

juju17

We along with 3 others own a property outright. We are all tenants in common. Each owning 25% share, although not sure where this is actually written.
One member (A) of the group needs £36k urgently. We are happy to stump up the cash for 20% of their share, with the agreement that they can buy it back at a later date for the same price.
All four people are listed on the land registry, so as (A) will still hold 5%, we assume land registry would not change and not have to be informed?
Whilst we all trust each other, we would want some legal document drawn up to protect everyone. Solicitor has quoted £700-£1000 !!, and cant do this before July. Plus if (A) does buy their share back, we would have to pay the solicitor again?
My questions are:-
Could we draw something up ourselves? 
Would there be any stamp duty/tax etc implications?
Many thanks.

getmore4less

It's not really a change in ownership.
 just a loan agreement is needed.

StandingInTheSun

Your solicitor is charging extortionate amounts for this. Our solicitor quoted £150 to draw up a similar sort of contract.

But in short, yes, these sort of things are possible. Uncommon, but possible.

juju17

Thanks getmore4less for your reply. I wasnt looking at it as a loan, as they may never want/be in a position to buy back their share...but what you say is helpful. thank you

getmore4less

If they can always buy back that 20% share for the same amount paid.
They just buy it back simultaneous with the sale   always get their 25%  less the loan amount.

If the value drops they don't bother.