got to admit I was surprised when you sold off all that kit last year axl (But understand there were good reasons)
the problem always comes in rebuilding
On a new warranty item I wouldn't ship cross border. Warranties don't cross borders unfortunately so effectively you are buying with no warranty ( I know you can get the 1 year international card by requesting it but if UK Pentax is like Canada they will charge an Admin fee for every service under it - $50 here i think)
The only way I avoid the damn taxes on used is like you value under a certain level ($30 here) and shipped through the postal service only. The couriers nail you at any value then add insult to injury with a brokerage fee that sometimes is more than the value of the shipment) learned that lesson and refuse to buy if it can't be shipped postal service low value
Fortunately at the moment Canadian pricing is so close to American on almost all the product it's not an issue. Film is the only thing miles out of whack.