Do I have to pay these surprise bills?

[YomAsalYomBasal]

I employed a company to do some work for me recently. Job all done now, not without its issues but complete at least. Now, 6+ weeks after my last invoice, I have received another large invoice. It lists a number of minor works, some of which were done with my agreement (but the costs are much higher than I was led to believe) and some I did not consent to at all. Others should have been in the original quotation but were not included by the tradesman. Where do I stand legally with this?

Please? It kept me awake most of last night

Did you have a contract?
Did you have a retainer?
Do you have receipts for what you have already paid? - with details of what you have paid for ?

Did the bills come in from the main contractor? Did he include copied of his subcontractors bills ?

Had he told you there would more bills ?

Bills coming in a long while after completion is not at all unusual.

Sorry, that was a lot if questions

did you have a scope of works for the original work and breakdown of costs, showing exactly what was included ?

We had a scope of works before we started, yes. It was very detailed - although the contractor grouped whole lists of items together and just put a price at the end of each page so it does not say, for instance, how many plug sockets were included. The additional items are now things like 'extra plug socket / extra aerial socket / light switch' Some are additional items I never agreed to.the ones I did we verbally agreed would come at no extra cost, they were in lieu of other items that ended up not needing doing. I don't remember signing anything, such as a contract.

The bills are from the main contractor, they carried out most of the works themselves. I have detailed invoices for what I've already paid and acknowledgement that I have paid them. I don't know what a retainer is I'm afraid