You dont have to wait 2 years before you start your MSc. Do it part time, or online. Do not take time out to do it. If you want to remain in the profession then you need to ensure you dont lag behind clinically.
As you will be a newly qualified Band 6, the department may not release you to do part-time M level modules. So you might find that you have to pay for it yourself and take annual leave for the study days.
Having an MSc will not gurantee jumping any quicker up the bands. As a clinical radiographer, we are always looking for radiographers who are competent clinically not high academic fliers. We want operators not academics running the linac and treating patients.
Try working in different departments until you find the right one for you.
My suggestion is work about a year in a department and do a CPD unit (which you might have to fund yourself). Become really competent in the job, work hard and after 1 year you are free to start applying for Band 6 jobs.
Depts with the latest technology are the best, because once you become competent in IMRT, IGRT, etc... then you can apply for Band 6 jobs in depts that are still in their development stage in this technology, which will make you more desirable as a potential employee.
Goodluck