I found some "Thin Client" PCs fanless PC boards (Fujitsu Futro S-400) from Germany, with these features:

* legacy RS232/LPT ports
* modern build
* fanless and silent
* simple power (12V 5A DC)
* PATA and CF sockets

I only need the LPT, the other features are just a bonus.

They were cheap at £26 but there is 20% VAT and over £10 of paperwork charges, which are an unwelcome addition.

I plan to install WinXP and the Dataman software.

I have a Tektronix pizza-box style case that might do, but the board needs to be upright for good convection cooling.

I have a suitable 12V DC PSU.

The PSU connector is a 4-pin thing but Toby want £4 postage on a £1 part. So I may simply wire power directly in to save looking for the plug.

2019-02-10 Finding it very hard to get this board going. Managed to make a bootable DOS drive on CF card but this won't run the WinXP installation files in DOS mode. I think the only way is to get an IDE CD-ROM drive and boot from that. Perhaps borrow one from an old PC? It is cheaper in time to just buy one.

I have found an old external drive that takes in 12V and steps it down to 5V, then both rails go to a 4-pin Molex drive power connector. I intend to use this to power the optical drive while it installs WinXP. Afterwards it and the optical drive are no longer needed.

2019-02-11 Salvaged an IDE CD ROM drive from an old scrap PC. Did not work, nor did either of two IDE hard drives I had. 

2019-02-15 Tried to get into the BIOS to see if it can be modified to try booting from the IDE port. I can't get in with DEL or F2.

2019-02-17 Tried raw copy of some existing XP disk files.  Could not delete files from Linux, had to reformat. Copied XP files, tried it, got "not a bootable disk" so I have to make it bootable again somehow.

Due to the international pandemic situation, I shelved this project for a while. I later looked for an alternative host.