Freddo - I expect that will much depend on the value of your order and how PakaDay decides to dispatch it. If HM wants to levy a charge her servants will advise you before you can collect.
I'm not sure what the limits are for postal imports to the UK but if it's the same as the personal limits allowed when entering the UK then that limit is £145 (assuming it is not classified as "alcohol,
tobacco or perfume"). The following advice from the Post Office may be of some help:
"Any goods imported into the UK over the value of £18 are liable to import VAT; gifts between private individuals over the value of £36 are also liable for VAT. Goods and gifts over these values may also be liable for Customs duty. As of the 1st of December 2008 you will no longer be required to pay customs duty for goods up to the value of £105, however you will still be required to pay import VAT and excise duty where applicable."
I don't think any of the goods should be classified as "tobacco, alcohol or perfume" but others have experienced problems and labeling will matter. The 1st December date is interesting and might be worth considering.
You should also be aware that a £8 additional charge will be levied by the Post Office if your package is stopped and found liable for tax.
Hope this helps.