Dear Kwill,
Glancing over your posts on this thread, it appears that you are a fellow US academic in the UK. I think I have a few bits of advice regarding tax and pensions for you:
First, it is great that you rolled over your US pension to an IRA before your moved over here. That means that, if you wish, you can
contribute money to your IRA from your UK income and deduct that contribution from your UK taxable income (and, of course, your US taxable income). This is in the Tax treaty. (You can contribute to your IRA if you don't use the Foreign Earned Income Exclusion; see below). Second, don't worry about filing UK tax returns on your UK income, as it is all taken care of automatically via PAYE. The only exception is if you had UK income outside of your employment. Third, and this is VERY important, you must file US taxes every year just as if you lived in the USA. You don't need to include a W-2 as you do don't have one. Fourth, DO NOT use the foreign earned income exclusion (IRS form 2555); instead, use the foreign tax credit; this enables you to pay your US tax via credit for the money used to pay your UK tax (IRS form 1116). Because the UK taxes are always higher than US, you'll never have to actually shell out any money to the IRS on your UK income. Fifth: here is the big secret: When you file your 1040, declare ALL of your gross Salary and include your employer's contribution to your pension. This way, when you finally draw your pension, it will be mostly tax-free as far as the US is concerned. Even when you include your employer's contributions, your UK tax should still greater than your US tax. Keep track of the excess UK tax you paid as you can bank that for 10 years and roll over to other years. Here is one crucial exception: I'm assuming you'll be in the USS pension scheme; that tax-free lump sum you will get will not be tax free as far as the IRS is concerned unless you have accrued a cost-basis. This is why you are better off if you include your (and your employers) pension contributions in your gross income. (Note: you cannot use foreign tax credit carryover against tax liability on lump sum pension contributions). Don't waste your time with a UK Stocks and Shares ISA. Seriously; you'll just get yourself in tax trouble and waste money on extortionate fees. Just invest in stocks etc. via your US IRA. That way, your investments will be fully tax compliant in both the US and UK. Of course, you can also invest (very passively) via the USS AVC scheme. It is good. You can also open a Roth IRA in the US and growth will be tax-free in US and UK. Note , however, that your US brokerage will not let you contribute to any mutual funds while you live in the UK. However, we are mustachians: we do not invest in mutual funds, we invest in index ETFs. Finally, be sure to file the FinCin FBAR forms every year if your UK savings (total) exceed $10000.
There is only one place to shop for food in the UK: Lidl. The prices and quality for meat, fish, cheese and alcohol are best. You will save a fortune.
Finally, if you haven't noticed this already, the way things are done in UK academia and US academia are VERY different. The main issues centre around teaching/grading/exams. Make sure you find out about how it is done in your department or you will always be getting in trouble.
Good Luck!
I hope this helps. Good Luck.