I went in for fuel once on the way to work (Frankly), but only because I was running on fumes and desperate, I put a tenner in and filled up later, there was an Asda one off the M5 at the Dudley Jnc but it takes longer there due to traffic lights on island,
I never go in for food or drink either, if you plan the journey there are usually other options, like the pub just off jnc 25 on the M5 (tea & coffee are an option) at the Taunton turn on the A358 South, as easy to get to as most services.