Transact SQL :: Getting Text Between 2 Characters

I have a column that is populated similar to below

[URL] ....

I need to extract just the 12345 portion. This will always appear after the first "=" and always be proceeded by &UL. I know how I can do this separately, which would be like

To get 12345&UL

ltrim(rtrim(
substring(
replace(cast(MyCol as nvarchar(max)),
'=',
replicate(cast(' ' as nvarchar(max)),10000)),
10001, 10000)))

And then I could run an update on the table after doing the above step using something like

SUBSTRING(MyCol,0, CHARINDEX('&',MyCol))

What I'd like to do is to have everything performed in one step, the above 2 SQL statements combined as one statement, so a separate update does not need to be ran.