Changed shipping quote price on me (UK)

Hey guys, I ship wine from the US and have a container which has landed this week with a well known global shipping company.

They sent me a quote in January for £2k - I then sent them the wine for shipping. There were various delays but it is finally docking this week. They are now asking for £4k.

In their terms and conditions it states:
8. Charges and Payment
8.1 Unless otherwise stated in writing, any quotations provided by the Company:
(i) Shall be exclusive of any taxes;
(ii) Shall be exclusive of any taxes, levies, imposts, duties or other such costs or expenses raised upon the Goods; and
(iii) Shall, up to the time of shipment, be subject to variation to take into consideration increases in fuel charges, currency fluctuations, freight rates, changes in materials or equipment under Clause 3.11 hereof, or other such expenses. If a quotation is so varied, the Company shall advise the Customer as soon as practicable.

I did not receive any such notice before the time of shipment (29/3). I don't think they can just double the price on me, can they??