Thanks for all the replies and suggestions.
This was the bulb that was got in the end, its a no-brainer, no need to cut springs or over tighten joints.
It's not too bright, it's the same weight as an incandescent and the real bonus is it doesn't get hot. After being on for hours you can grasp the shade and its barely warm, meaning its kind to the shade and the switch. It said £8 on the box, my missus got it for £3
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With regards to dating the lamp, I looked through graces guides etc. and I could only see similar but nothing exact. There are specialist websites/sellers that I have found around that I can enlist help from in dating it.
Regards
Poppydog