Because you are new, and in another country, may I suggest you post in the area you live in? We do not know what is selling or not, or what homes go for.
Thanks

While real estate markets are all about location, some general facts remain true no matter where you are located. On sale for 3 years with only 2 serious offers usually translates into overpriced. You need a new real estate agent with a fresh outlook to analyze the market to see what has sold, and at what price. If you don't "have" to sell, it might be best to just stay put and take it off of the market.

What you paid, and then invested, does not have a lot to do with the value of real estate (in ANY market).

Lower the price.

Can you post the MLS link so we can make suggestions about what potential buyers see?

I would bet they don't have "MLS" in England.

isadora4 - is the property listed somewhere on the internet? If so, can you post the link.

Can you explain what "Freehold" means, that's not a term we in the US.

I believe that "freehold" is how most property in the US is held.

Freehold defnition: Exclusive ownership of property for an indefinite period. In contrast with leasehold, which is the right to occupy property for a fixed term.

In Canada, "freehold" is most commonly used to differentiate condo townhomes from freehold townhomes. It is understood that detached homes are freehold, so this is not an issue.

"The main and most important difference between Condos and Freeholds is in the area of land ownership. In the case of a Condo Townhouse, the actual inside of the unit is owned. However, the outside of the unit and the land surrounding the unit and all the other units, driveways, lawns, gardens, etc. is owned collectively by all the unit owners, and is called the "common elements". Each owner pays a monthly maintenance fee covering such things as grounds maintenance, common element insurance, and general upkeep of and outside maintenance of units. ... With a Freehold townhouse, the owner owns the lot and house individually as one would in a semi or detached home and there are no maintenance fees per month. Owners decide at their own discretion when to replace the roof or repave the driveway, and, of course, the expense of doing so is theirs alone."

Properties in Hawaii are usually either Leasehold or Freehold. A lot of land is owned by some very large old trusts. (Think Dole, Hawaiian Land and Pineapple, and some properties that date back to Hawaiian Royalty and benefit charities.) A trust 'rents' the land under your home to you at a set rate for various lengths of time: Fifty-to-100 years in many cases. That's Leasehold. These homes sell for less than comps that are Freehold, and your RE taxes may be less, but you must pay the 'rent' on the land. Selling one of these properties gets dicey when a lease is near expiration!

Freehold is more common in the rest of the USA. You own the land and the improvements on the land (the house, etc.)

AFAIK most condos are set up so that the condo owner 'owns' the interior of his unit while the rest of the property is owned by the condo association as a whole. The condo owner pays RE taxes on his unit and pays fees to the association, which pays taxes on the whole operation. (Fees can cover many other things like exterior maintenance, landscaping, utilities, etc.) There are also 'co-ops', where I believe you buy 'shares' in an association that owns everything in common.

To return to the OP: Read the posts here from owners everywhere who have been unable to sell their homes. If you need to sell...it's usually only going to happen if your price is fair in your market. Some people are having a hard time because buyers don't qualify under tighter mortgage terms. Can you rent the flat or help a buyer finance the purchase?