Anglo have joined the 2009 Irish guarantee. This covers any term deposits that are opened before September 29th 2010 until their maturity date. Check yourself, but I think Anglo IOM term deposits are included in the guarantee.
You will not get a much better GBP rate than Anglo IOM.
Most Irish banks that offer GBP deposit rates, do not offer very competitive rates.
If you do not wnt to go with Anglo IOM, I suggest that you look at opening an account in Northern Ireland and check out the GBP best buys on a UK website.