I have a large deposit alreadyWhat I'd recommend is that you time the purchase of your 2nd property. ie Save up deposit now to buy number two when the crash comes your way. I recall back in 2008/09, mortgages were very hard to come by unless you put down 40%. You can then sell the first one when market recovers and await your time to invest your cash for the subsequent crash.
That's assuming housing market does crash in the UK, which I do not think so due to fundamental infrastructure reasons. What you suggest occurred in Ireland and Spain with total over building - excess supply. However, UK market significantly different with much stricter planning controls on land. We have excess demand. House prices, like wages are sticky downward. People will prefer to stay put rather than absorb loss. i.e. much like holding on to losing trades.
Good luck but don't hold out too long if your plan doesn't materialise in good time imo.