H's is great. The last order got here via DHL to the land O' Fruits, Nuts & Flakes in about 3 days from jolly old England.
Go to their website, create a membership, get a customer ID#. This gets your name & address into their database, a time-saver.
What I do when ordering:
Just go on their website, research/peruse the parts you think you'll need. Copy the part numbers down, or "copy 'n paste" into a text doc.
When you're ready to actually purchase, log on to the H's site. In the "Search" bar at the top of the screen, type in your part number, press the "GO" button adjacent. The part comes up.
Select "More Details". Set quantity & select "Add to Basket".
Type the next part number into the "Search" bar, repeat as necessary, or until the missus twigs to what you're about.
When done spending like a drunken sailor in Hong Kong, select "Checkout" at the top of the screen.
You can use a credit card to check out, they have a secure site. Follow the prompts. DHL as shipping has worked excellently for me, usually just a few dollars more than Royal Mail & much faster. They offer up a PDF of your order when done. "Save As" to a "Hitchcocks Purchases" folder for future reference.
After your order is complete, go out to the garage, look at your bike & suddenly remember else what you forgot to order...
On small bits, like washers, o-rings, gaskets, Whitworth fasteners, etc., I usually get a few extra, as shipping is prohibitive for a single cheap item and a hinky thread on the last Whitworth stud can set your program back a couple weeks.
Remember - "You can't be out of money if you still have cheques left..."