Heartbreaking property situation or not?

[Muddle2000]

Cousin has been living in her Council home for 20 years.
She has been offered a near 50% discount under the Right to Buy.
Snag. Japanese Knotweed -small patch- noticed growing right
under her back window .
Obviously it can be treated with indemnity etc
I have heard JKW can lower the property value by up to 40%
She could never afford to buy a house on the private market
Should she go ahead or just call it a day?

Why would it be a huge issue?

She can't buy elsewhere, if she sells she's still made at least 10% profit and in the meantime a 50% mortgage will be cheaper than her current rent.

I'd buy it.

It can be really hard to get a mortgage in this situation. Has she had one approved?

JKW has got really widespread, with estimates that 10-20% of London properties actually have it but just aren't reporting it.

Is the discount off the market price, in which case the market price should reflect the JKW?

Surely as it's been found before the sale she tells the council it's their duty (which it is) to eradicate it and she will only buy on that basis?

The Council have said they have never come across a situation like this
which I do not believe.
They sent a guy round and then the offer of a further 3K discount came.
They are liable but just seem to want to get rid of it.
Eradicating it could cost a bit eg pulling up garden paths.
The thing is the plant has been lying dormant for years. She has been
-until now- just cutting it as it was only a tiny bit- unaware it was JKW. She left it this year and it has grown but nothing terrible.
NotCitrus- the discount is off the MP. A good deal really.
I have suggested getting an eradication quote and then presenting it to
the Council for a further discount as they are just evading it
The problem with not reporting/leaving alone is that if you sell and
the new encumbants discover it you can be sued retrospectively

I don't think she'll get a mortgage unfortunately.

She needs to speak to her solicitor, get a proper one not just a conveyancer, and make sure she gets one by recommendation not just uses the one the bank suggests.

It should be feasible to get a mortgage, but I'd go through a broker to be sure (which I'd do anyway), as long as a contract for eradication is put in place - which is probably less than £3k but there will be a couple years of not being able to plant/lay slabs in the garden. A solicitor should be able to sort it.

From the Council of Mortgage Lenders:
"Mortgage lenders will normally require evidence of treatment that will eradicate the plant as a condition of lending if knotweed is present on or near the site of a property.
There is an Environment Agency Code of Practice for developers on Japanese knotweed; and a Royal Institution of Chartered Surveyors information paper with an addendum published in September 2015 aimed at informing valuers of residential property.
Lenders determine their individual policies on this issue and take into account a range of factors when considering whether to lend.
Valuers who inspect property for mortgage purposes are instructed to report to lenders where knotweed is present. The pre-contract enquiries that conveyancers seek as part of the legal process also ask whether Japanese knotweed is present.
There are legal restrictions on Japanese Knotweed. Lenders and customers are therefore likely to need professional help with remedial work. Similar considerations apply to other invasive species."