Unfortunately in UK, most companies want you to have the local ones, CREST and CHECK, and of course SANS. OSCP doesn't sell as much as them and ISC or EC-Council.
My advice for you would be to first start with CEH, then GPEN and with a more experience, you can go for OSCP.
To be honest, OSCP is not an entry-level into the world of PT, I would first suggest you to practice all the Metasploitable, DVWA and those tutorials, get a couple of books like Metasploit: The Penetration Tester's Guide, Advanced Penetration Testing for Highly-Secured Environments: The Ultimate Security Guide and most importantly, motivation, and practice.
Now, having these certifications is a plus, but when you get an interview, at let's say big 4, security boutiques, telcos and the like, the most important is for you to be able to communicate the issues with the client at all levels. The thing is, there is no real way to "learn" that. Apart from that, you need to have solid networking skills, understanding of OS, databases and how everything communicates, basic scripting and the like. A very simple question like:
Let's suppose you're doing a PT, and in the middle of it, you trigger something, the exchange server crashes, client wants you to continue with the PT and meet the deadline but without touching the exchange server
The best for you would be to get a job as a network admin, (junior pentest opportunities are out there, but extremely hard to find) and most of these...well they won't teach you anything you cannot find on the internet, they will most likely never send you to meet with a client and discuss how you're going to scope a pentest and the approach you will take.
Good luck really! Try maybe working as a security consultant and talking with the guys that do PT and gain experience, it's a lot about self study.