Hi Fortune
You could do a spreadsheet. You would have to make a lot of assumptions. So they would be guesses.
But my point is that my informed guess is that you would be financially better off buying a house and delaying starting your pension than starting a pension and delaying buying a house.
But the non-financial aspects of owning your own home and the security it provides would hugely outweigh any financial disadvantage, in the unlikely event that my guess turns out to be wrong.
Brendan
There are a couple of points that are probably correct from a purely financial perspective.
One of these is that buying a house is a better move financially than renting, in normal market conditions all other things being equal etc. etc.
What is less clear is whether it is better to out down a minimum deposit and pay off mortgage as slowly as possible while starting a pension, or pay off the mortgage as quickly as possible and delay the pension. Either way you are out of the rental market horror and benefit from likely house price increases.
So on that basis , and assuming the OP needs 3 years of accounts to get a mortgage then I reckon that over the next 3 years the OP should regularly save, in a savings account with interest, about 40k - 10% deposit on a 400k property.
I would then be inclined to put additional savings into a pension up to the maximum allowable contribution 15% of 115k.
Beyond that, there's a choice to be made for any additional savings - cash which could be used to pay off property more quickly, equities or potentially additional pension contributions if the OP has or gets a Ltd Co.
Personally I spent my 20s having a ball and not saving any of my meagre income and I have no regrets. If I was the OP, I would be spending a chunk on having a good time with lokeminded friends to last a lifetime. But before that, I would get an accountant.