I second what Bookworm said. I think it's a question of applying a bit of thought to what is actually required rather than following the list printed on your kneeboard. Whilst the information is standardised in CAP413 it clearly doesn't make sense to follow it to the letter every single time. Who you are, where you are and what you want is a good starting point.
If you're flying from Elstree to the east coast and back, Stapleford radio don't need to know anything about your route other than you're from Elstree eastbound. They don't need your precise heading either - if you're from Elstree and heading east your heading is going to be about 90 give or take 20 and what would they do with the extra info if they had it?
My RT examiner chastised me for using words like 'currently', 'overhead', 'we are' etc. Clearly it doesn't make a huge difference in terms of transmission time or comprehension so not worth getting hung up about, but it does make your RT sound snappy, efficient and more professional. Thinking about it 'currently overhead' is particularly daft (and don't get me started on 'at this time' - do airline cabincrew get a bonus every time they use this phrase - I heard it three times in one sentence on a recent US trip).
So putting it altogether:
'G-XXXX is a PA28 out of Elstree destination Elstree currently 3000 feet on QNH 1023 currently overhead the Lea Valley, via Stapleford, Southend, Clacton, Southend, Stapleford. We are requesting traffic information'
becomes:
'G-XXXX PA28 Elstree to Elstree, at Lea Valley, 3000 feet on 1023, eastbound, request traffic information'
or even:
'G-XXXX PA28 Elstree Elstree, Lea Valley, 3000 feet 1023, eastbound, request traffic information'
Mind you, whatever you say to Stapleford they still seem to call you sir in reply, which is nice, unless you're a woman.