Thats odd. (I work in insurance, backend software dev).
Insurance Premium Tax (IPT) is specifically 12%, its a bit like VAT for insurance. Them saying the tax is causuing it to almost double its absolute bullshit.
100 Premium = 12 tax, total of 112. If your premium is was to double “because of tax”, either they messed up on the tax calculation (say 120% instead of 12% tax would “double” the total)
There was also a change in the last few years regarding “premium walking” where your first year is basically an undercut price, and each year after the premium increases. Now they have to offer the same price to new and existing customers.