I filed an online airprox in early May, with a paraglider. The Airprox report was out in July. I found the Airprox guys good to deal with. I wasn't receiving a service, but monitoring 127.275. If I'd been changing frequency, or entering a squawk, I could have hit him. The report has a link to the YT video.
PS The suggestion of monitoring 135.475 is OK, with a second box, but I wouldn't want to lose Scottish.