I am you. Or, at least, my DS1 is yours!
Briefly (as I can!): DS1 was 'being 15' during his GCSEs. Achieved one grade point lower than predicted in 6/10 GCSEs, but still 
started A levels in Maths (B in GCSE); Physics, Geog and Economics at a good, but 'forgiving' 6th form. He also had a B in Computer Science GCSE.
By mid lower 6th, we all knew it was Going Wrong. Same 'meh' attitude.
By luck, I had a convo at work (I am a HCP in a degree level entry job); where a 'lad' said he'd messed up his AS's so transferred to restart, via a '3 A level equivalent BTEC Extended Diploma' (in Applied Science); thence onto the HCP degree.
So I did my research and unearthed the same level BTEC in Computing at a nearby Technical college. I had no idea it existed!
So off DS1 went (via a D, and E and a U AS level.. ) to Tech.
It was a very different experience; no bells between lessons, no 'Parents Evenings' or week by week 'progress report' (maybe because it was a Tech?) but 8 in his class. Also, being BTEC, constant deadlines. A fiendishly complicated way of totting up achievement. Some 30 point modules, some 90; 4 external exams. But the students seemed to know exactly where they stood!
DS1 hit his stride. Left with D star, D star, D (D= distinction). Now at a well rated ex-poly (Y2) doing Software Engineering.
So, the downsides? He could only do something computer-y with the BTEC (tho I feel we allow kids to not specialise in anything in the interests of keeping 'all options open, always', even unto 17,18 in the UK). He also couldn't apply for 'Computer Science' at a RG because they demand Maths A level alongside, and want an A grade.
DS didn't want to do Computer Science, he wanted to do Computing. There is overlap, so check exactly what the uni course involves. People use the term interchangeably.
Note 'Computer-y' subjects at uni have one of the highest drop out rates (10%+), because the students don't know what they've let themselves in for!
The upsides? Having a relatively easy Y1 at uni as he has covered so much of what they're teaching, given that he spent all of the last 2 years doing 'Computers', whereas some had only done 1/3 of those two years doing CS 'A' level.
Already able to code.
A scholarship for his good grades.
25% of students access uni via BTEC these days. We aren't talking Oxford here, but- a thought. It has been said that if your chosen course has more than one word in its name- maybe an ex Poly? 
.
No one cares if your software engineering degree came from which uni, within a (wide) reason, as long as it's a solid 2:1, and you can account for yourself. If the employer is looking for RG graduates, they're probably not looking for my son!