mao44 wrote:I guess it is a toss up between iweb and Vanguard but leaning towards iweb with their zero platform fee.
If you plump for iWeb, probably best to move your holdings intact, rather than as cash. You could switch to the Vanguard equivalent inside iWeb after the move (or perhaps in HSBC before the move, if HSBC's platform permits). Or not at all, because frankly I don't see much in it between the two funds, and I hold both personally. iWeb lets you hold HSBC, Vanguard, Legal and General, Blackrock, Fidelity, and so on -- all of these are reputable tracker fund providers. A transfer of holdings could be slow, on the order of months, but involves no out-of-market stress. And you can pay in to the new ISA account while the transfer of older holdings is taking place; the receiving company will merge the transfer with any new holdings you bought there once it completes.
If you plump for Vanguard's platform, you will only be able to hold Vanguard funds or ETFs there, at least currently. That would mean you would have to sell your current HSBC holding and transfer the ISA in cash. This will be faster than moving holdings intact, but with some out-of-market time. (Which of course could go either way, but for me has always seemed to go against me -- somehow I always manage to miss a stock market rally rather than a plunge!)
In all cases, remember to transfer the ISA itself. Don't cash everything in, withdraw the funds to your bank, and then try to move that yourself. It won't work that way. Contact the receiving company, iWeb or Vanguard, to have them open a new account for you and then manage the transfer in for you too.
Finally, if this is your only investment, maybe consider branching out beyond UK all-share to something more global. The UK is well under 10% of world market cap, so if you only hold UK stocks you are not well diversified geographically. There are several all-world funds you could use instead, or you could complement your existing UK all-share with an ex-UK tracker fund.