costs of developing a victorian split level flat

[imme]

DH and I are contemplating buying a large 2 bed split level victorian flat for a fairly decent price. the place needs complete gutting, redecorating, new kitchen and bathroom. not sure about gas and electrics. eventually new doors and repair/paint window frames.
are we unrealistic in our cost estimate of 20-30k if we are prepared to do a lot of the work (like paint work) ourselves? we are not looking for any fancy stuff, as long it's clean and decent...

would be great if you could share your experiences..

cheers!