There is no needle, the metering is indicated by a traffic light system in the right of the finder. Red at top and bottom, green in the middle and amber between the green and reds. They can be difficult to see in bright light. As mentioned, check the batteries are in the right way (it looks the wrong way).

I think for smaller diameter lenses (especially if it's on film), Cokin P filters are more than adequate, there may be a slight colour cast which might be a problem if shooting on chrome film for projection. The larger 'pro' filter systems are much more expensive and only really needed if you're using large diameter filter threads and need the extra hieght of a 150mmx100mm grad filter or are extremely dedicated about landscape.

I use a Cokin 'P' circular polariser up to 77mm filter threads without problems (the Lee equivalent is several times more expensive). I also have their 3 pack of ND filters (which if added together come in at around 6 stops) but I've never used them so can't comment.

SOLD: Sold elsewhere, thanks for looking.

At least with a Pentax adapter you know what you're getting. With an unbranded one it's pot luck, a branded 'non-Pentax' adapter might be perfectly fine, the branding gives you the opportunity to identify it and locate reviews etc. I doubt very few good quality branded 'non-Pentax' adapters are much cheaper than the Pentax one.

Note: Some online sales show (or describe) one version of a product and ship another.

*Update:* This has now been reserved.

I've put my DVM across the earth & centre pin contacts, I get somewhere around +3v with the gun charged - dropping to 0v as the flash is triggered. This was a kind of surprise and I can not verify this test is meaningful and wouldn't recommend using it on a digital camera (it's pointless anyway on anything that doesn't support 'old school' TTL flash).

Trigger voltages before electronic cameras were very high (I have a Vivitar 283 that exceeds 270v), at some point it dropped to 'reasonable' levels (either when dedication or AF came in). I don't know whether this is below the 5v range you might expect for a digital camera or in the 10-15v range. I expect many AF film SLRs are equally susceptible to high trigger voltages, the difference is that today, very few of them hold a significant value compared to a DSLR.

As I'm interested in mounted slides, it would help if the mounts were dated with the processing date (Kodachrome used to do this). Do any of the above mentioned processors do this?

It relies on the cameras TTL flash sensor during exposure (it doesn't have it's own sensor - like the Pentax AF240FT etc). So it will measure bounced flash correctly if the camera supports TTL flash. Not sure if it works jn TTL mode on a manual focus body.

I've also found the box and wide-angle diffuser for it.

For Sale; Miranda P-AF 36 flash dedicated to Pentax AF film cameras with TTL metering. It specifically mentions the SF-7 & SFXN but it works with the Z-1 and I presume with other AF film SLRs with TTL flash metering.

GN 36m @ ISO 100 with bounce & zoom head & AF illuminator.

£15 posted to the UK.

Looks like the SilverPan film lab will shortly close until September:
https://www.silverpan.co.uk/our-processing

Thanks for the suggestiond. The £10 for Ektatchrome offer at Analogue Wonderland has prompted me to try it out. I'm also considering silverlab given the discount.