Yes, Thames streamer is basically just the areas immediately around the estaury and Luton is no where near I'm afraid so that wont effect you. I wouldn't think you will get much until later tonight /tomorrow that's when it seems to be forecasted, as for here too, the showers coming in over London are dying out before getting 40 miles to the west where I am, I am expecting a small covering though by morning but shant hold my breath as in these situations usually everything passes to the south of me and goes through Surrey/Hants