Hi BTU
There are several centres of excellence in London should you need them – UCL and Royal Marsden ( Sutton ) have some of the top UK specialists and are well organised ( around waiting times and renting any necessary scans ) – you will need referral from your GP and maybe a firm nudge !
Sounds like you are already measuring light chains and Paraprotein ( two key markers ) but there are other factors that will be considered before any diagnosis /staging … good news you are feeling well….
If you need treatment the good news is that there are many excellent meds available and the advances over the last few years have been good news for patients with more in the pipeline …
If you are someone who likes to get informed I recommend http://www.HealthTree.org which is an American site full of excellent educational resources ( Healthtree university )
Good luck with next steps , completely understandable to be anxious so stay strong and one step at a time …