Thank you. An estimate will be just that, it is not a formal quote as such but will still be a rough indication of what the work may cost. In the end, you will still have certain rights under law. When a person enters into a contract for work and materials, where the main focus is labour and skill, the Consumer Rights Act 2015 says that the work must be provided at a reasonable cost (unless a specific price has been agreed).
In addition, any information exchanged in communications between the parties, whether written or verbal, is binding if the consumer relies on it. This will include quotations and any promises about timescales or the results to be achieved.
If there are problems with any of the above, the customer will have certain rights. There could be a cost disputes, where traders can ask for additional money either during or at the end of the work. This is why it is preferable to have a written agreement in place, setting out what price was agreed and what for, so that you can both refer back to it. Any price variations for extra or amended work should have been agreed in writing before the work was done. If you knew that this extra work was being carried out and let the trader continue then a reasonable price would need to be negotiated for it as it may not be possible to completely refuse to compensate them for it. This should however, prevent them from charging for work which was not agreed or communicated.
You can offer what you believe to be a reasonable price for the work undertaken. If they refuse to accept it, you do not have to pay them what they ask for. It would be for them to challenge you further on it and the only way you can be made to pay is if they go to court and win, which they may never actually do. So do not hesitate to stand your ground at first, you can always negotiate further down the line if needed and can always put a stop to a court claim by paying what they asked for.
Does this answer your query?