Thanks for eveyones help, a lamp kit has been orderd from Martin(Dillen).
As an aside, I buy quite a bit of vintage hi-fi gear from my local tips - some of which I keep - some I sell on. You'll be glad to hear that I intend to hold on to the Beomaster as I just love the iconic design and the era it evokes. Despite this, my curiosity has the better of me and I wondered if anyone could give me an idea what the current market value of a 1900 in good working and cosmetic condition is? I can't find any record of one being offered for sale on this forum and the only one I found on ebay was sold as untested for £20.
I hope this question isn't seen as bad form as I know market value does not necessarily reflect the personal enjoyment of ownership - I'm just curious I guess!
Nigel.