Are you sure the issues you are talking about are related to Baldurdash and not Dudleyfix? I am 100% sure that area transition to Ulgoth's Beard was broken when applying Dudley patch (the entire package, not individual fixes), but haven't experienced this with Baldurdash.

I haven't used Dudley fix, so I cannot comment on that, but the couple of times I used Baldurdash, Ulgoth's Beard transition was broken.

I have just run a test, with GOG's BG1 - The Original Saga with Baldurdash fixpack on top of it. Ulgoth's Beard is accessible from the north edge on both sides of the river of Wyrm's Crossing map.

Opening the Baldurdash fixpack archive you can notice there is no AR0900 file which means it does not mess with the Wyrm's Crossing map, from which you travel to Ulgoth's Beard. You must have had some other mods or patch that broke this area.

I play vanilla. I don't install mods.

It has to be run from your BG1 or BG2 root directory. ie the same one dialog.tlk is in,

Edit:
When you run the widescreen.exe, the first screen says Destination Folder.
That is where you Browse to where you have installed BG1 or BG2
The Default destination that you went with, is the default location of the disk version BG2.

Uninstall the game from 'Program Files (x86)' and reinstall to somewhere like C:\Games\Baldur's Gate\. Games should never be installed to Program Files, because Windows places any data that needs altering by either the game or yourself -- that includes mods -- into a virtual folder. Once you have done that, extract the mod to the main Baldur's Gate install folder, so you have something like:

C:\Games\Baldur's Gate\widescreen\
C:\Games\Baldur's Gate\setup-widescreen.exe

Thanks! I will tell you if this fixes my problem

Thanks to your help I now have it installed, although when I launch Baldur's Gate:Tales of the Sword Coast it is still in its old low resolution. Is there an obvious second step I missed to get the game running widescreen? Also my resolution is 1366 x 768

Non standard screen resolutions (1366) are not supported in full screen. To play in full screen you need to pick a standard resolution for the widescreen mod. With 1366x768 being a 16:9 resolution, you should choose 1280 x 720 instead.

I have now entered the resolution as 1280 x 720 but now when I launch Baldur's gate the game only appears in the top left hand corner. Blackness surrounds the rest of my monitor. I am, however, still able to move the Baldur's gate cursor around the blackness. Thanks for being patient with me.

I have a 1366x768 laptop myself, so I checked there. Baldur's Gate was unfortunately uninstalled, but Icewind Dale was still around, and they use the same .exe for widescreen I believe. Fired up the game, and loaded a save, and sure enough, it was in full widescreen. So it looked like 1366x768 should work.

Not much help perhaps, but if it worked for me, it should work for you too.

It could perhaps be that something got messed up when you tried the faulty install of the widescreen mod (re: your screenshot), so maybe a clean install would do the trick? I know I've seen that error before, and I think it was when I made the error of installing Tutu with a BG1 install that was tampered with (it has to be completely clean, so no mods and such shenanigans).

So, if you have done the same, Tutu with a BG1 install with some mods (fixpack for example), then you probably need to start over. At least that was my experience.

Now you need to set the game to display to your monitor's aspect. To do this open your video card driver control panel, and set (for example in nVidia) desktop size and position: 'Aspect Ratio' and 'Perform scaling on Display'. If you find this displeasing (squished), then set 'Perform scaling on GPU', but this will leave black borders.

This option does not seem to appear on my control panel (see attached), is there any other way to do this?

Not even an option to change resolution? I've never seen that before. Go to the nVidia website and download the latest drivers for your computer. Once you've done that, uninstall the current drivers via Control Panel and install the downloaded ones. Make sure you choose to perform a completely clean installation in the setup.