My lamp, purchased many years ago (approx £240 at the time) from a supplier in London is a mains powered handheld dual-bulb lamp ... shortwave [peaking at 254 nanometres] + longwave [peaking at 365 Nm]" It is referenced as "UVL 58" and was made by the UVP company in California.
Do a general search for "uvgl 58" and select images to see what the lamp looks like.
The UVP company has now been taken over by a German company, but still using the
https://www.uvp.com web address.
I find the new site not so easy to navigate for info, but there is a direct link to a dealership list at:
https://www.uvp.com/europe-africa-middle-east-dealers Look for the entries under "UK" and then I suggest a bit of browsing to see which dealers, if any, can supply the dual-lamp version and to check priices. You could also try eBay etc. but you may not get a brand new one with unused bulbs that way.
That should give you an idea of good quality units and their prices.
There are cheaper ways to go with battery powered units. However,
I suggest being very wary about small "pen" type torches for shortwave use. I once bought one on ebay via Germany but made iin China (called "Lighthouse"). It was poor manufacture and the on/off switch was stuck in a permanent "on" mode. I did not realise that when I put the batteries in - which had to be done with the body cover off the lamp - and I got a brief shot of uv to the face. Dangerous!!