Clueless

Hi folks, Given recent rise in the value of houses (plus a quick check on Zoopla) it looks like I could potentially remortgage and free up £30,000+ in equity on my current house giving me ~ £40k (with savings) to invest along with my father who is potentially looking to invest in a self build for a holiday let. Would it be possible for him and I to get a joint mortgage with 40k deposit each (£80k total) for a ~£220k build to run as a holiday let and family holiday home? Please excuse the naivety of this question, but my current property is my first property and a mortgage advice center did all the heavy lifting for me on this one and my dad is from a generation where houses cost £3,000 and hasn't had to deal with mortgages in a long time. We'd be looking to have the whole build done for us with maybe the exception of project management if the saving on doing that ourselves is substantial as my dad spent 40 years in the building trade. As far as managing the listings and calender of a holiday let goes the plan is for my wife to do this while I continue working. Any and all advice would be great, thanks.