After much searching and checking I've go for a new iPad Air and Pencil and it's coming tomorrow.
I believe it is now possible (IOS 13) to move files across in a 'Windows Explorer' type of way?
I've seen possible use of a Lightning to USB adapter or something like an iStick memory stick ... what is the best way to go and does it really work transfering stuff over?
You didn't say on which operating system, but since you mentioned Windows Explorer (now File Explorer), yes it does. Usually.
You tap the icon that's three dots in a circle near the top left of the screen in landscape mode (in portrait mode, tap the Browse icon at the bottom right to see this icon), and then tap "Connect to Server". You can either enter a server name or an IP address. If you don't know the IP address of the PC you want to connect to, open the Settings, click Network and Internet, then View your Network Properties. The IP address you want is the one next to "IPv4 address". Enter this in the Server field on the iPad then tap Connect.
If this is the first time you've connected to this PC you'll have to enter your user name and password, then tap Next. If you've connected before, these fields will be already filled in for you. After you tap Next, you'll see any shares from your PC. If you haven't set up any shared folders, here's
Microsoft's help page on the subject. (Even if you have, I'm assuming others will be reading this post at some point.)
The connection should stay up until you restart either the PC or the iPad, or if you deliberately disconnect. To disconnect the PC from the iPad, look down the left hand side of the iPad's Files app and look under Shared and you should see the PC listed by IP address. There should be a blue eject icon to the right.
For a long time there have been problems with the Files app when connecting to PCs, though it seems to work fine on Macs. Sometimes the iPad just refuses to connect, and it usually looks as if either it can't find the PC or the PC is rejecting the connection. As it's an iPad, there isn't a log file you can check - at least on the iPad end; you might find something on the PC. If it doesn't work, you could try restarting either the iPad, the PC, or both. Or just use a USB stick or Dropbox to do the transfer.
Since you have an Apple iCloud account, you could install
the Windows 10 version of iCloud. This way you can drag files into the iCloud Drive folders on one machine and retrieve them a short while later (sometimes as little as one second, depending on speed of connection and how clogged up the tubes are).
If you (or others reading this) aren't familiar with how to use the Files app here's
Apple's support page