Ok, thanks got this far and it works.
Now I've noticed that if I try and enter a number the number gets repeated many times in the display window. For example trying to enter 3 GHz for stop frequency places 3 333 in the display window, or if I enter 1 I get 1 111 111 111, or 8 I get 8 888 and so on.
I'm using Safari browser, so definitely a bug in the UI.
Later may try and get this browser feature working on the RPi under Raspian if I can.
Anyway, thanks for the help.
Edit: Just got this working with Raspian (Chrome) and it works OK, no issue with repeated numbers?? While Chrome is running the Safari interface works without repeating numbers, but without Chrome the Safari interface reverts back to the multiple number effect?? Also noted that Chrome is more responsive than Safari and even Safari gets slightly more responsive when Chrome is active??
Interesting effects, but the little RPi seems to work nicely with Chrome and the Siglent web browser feature!!
Another pleasant surprise from Siglent gear, now if they would just enable the SDG2042X for web browser
Best,