Baddoch

GordW, Jerryy and BobJ - thanks all for your taking the time and trouble to reply - I've been a bit busy with family stuff  and only got round to looking at this today.  GordW - thanks - you get the gold star, I followed your advice and cards now functioning properly.
Best to you all
 

Something does not seem right.
Uncompressed raw files for the X-T5 are supposed to be around 80MB, call it 85MB just to be safe in that assumption. 183 x 85MB = 15555MB, which is about 15.6GB. Even if you are using full sized, fine jpg along with the uncompressed raw files, you would not come close to filling a newly formatted 64GB card with 183 shots.
Maybe try a new card?

Sorry, I didn't finish that comment. I don't, know what is going on but yes, try a different card. Also, always format the card in the camera. I expect you did, but I thought I would mention. There is no point in not using lossless compression by the way.

If your image frame numbers with the X-T5 are "99xx", my first thought is that your X-T5 is set for "Continuous" frame numbers and your card has run out of available numbers up to 9999. But, that your X-T20 is set to "Renew"
Go to Settings > Save Data Setting > Frame No. and choose "Renew". Reformat the card. 

Hope that helps.

OK there are two things here:
- you are seeing the File Storing message because you have Clarity set to non-zero - if you don't like the message change the clarity setting
- if you want to always see a preview of each image after its has been taken there is a menu setting:
Set-Up -> Screen Set-Up ->  Image Disp.
You can set it to display the image for 0.5 sec, 1.5 sec or continuous until you dismiss the display

Hi Baddoch. I have followed a similar path from Pentax. 
It depends on your perception of small/smallish. If you are looking for something to act like a normal "pop-up" flash, the EF-X8 works well. 

If you are looking small, I would look for the Godox TT350-F. I pcked a couple up second hand from LCE around £25 each. (Think Pentax AF360 FGZ but a bit smaller)

If you are after a "full size" one, I would go for the Godox V860III-F. Just before Xmas I picked a couple up brand new from Amazon at £91 on offer with a voucher. Fantastic flashes with Lithium ion batteries and fully compatiple with the Fujifilm TTL modes as well and integrating with the other Godox units and guns including the TT350. These are still available on Amazon for £153 but there is a voucher code for 30% making them £107, Compared that with over 4x for the Fuji unit which is less flexible.

It depends on what you're after, but for a good all-rounder unit I purchased the GODOX TT685II-F for my X-T5.