You will not get an adjustment after starting, and annual increments are in the order of 1-1.5% (if your're lucky). It normally takes about 6 years to make Senior Engineer REGARDLESS of previous experience.
My advice with the current GBP exchange rate and the expected long term weakness of the US Dollar, you would be foolish to accept anything less than $40k/month.
BTW what section in TS are you planning to join?