Lump Sum Investing. The Vanguard report (
https://pressroom.vanguard.com/content/nonindexed/7.23.2012_Dollar-cost_Averaging.pdf) shows results for Lump-Sum (Lump) vs Dollar Cost Averaging (DCA) investing.
Since you have an indeterminate withdrawal date, you should consider treating it as any other investment, and putting it in a mix of investments that meet your investment risk tolerance. MMM just did a post on investing $400,000 (US) and broke it down in a mix that might also work for you.
40% Vanguard Total Stock Market Index Fund (VTSAX, VTI, or a TD Waterhouse equivalent fund in CA),
40% Vanguard Total International Stock Index Fund (VGTSX or a TD Waterhouse equivalent fund in CA),
10% REIT fund (be a 'paper landlord' without having to fix toilets), and
10% Bond fund (this is purely insurance in case one of the 40% investments tanks in the next two years - your risk tolerance may make you want to put more $$(CA) in bonds, but for total returns you can't beat the stock market over time).
[yes, I realize MMM is doing the lending-club thing; for myself , I don't have the risk tolerance for that, so recommend bonds - it helps that I'm older than most mustachian's here, and am on my 2nd shot at FI... that's a story for my blog -> coming soon]