Millage allowance when selling

I have been letting a flat and since the Tennant left have decided to sell. After the tenant left I have used a contractor to do a full refurb and I have done a lot of milage going back and forth to meet the estate agent, meet the builder, check on his progress, pay a visit as was informed there was a leak into the flat below, all in all we are talking 1600 miles so far. Logic would state this would be deductible am I correct and at what milage rate? Travel time alone its a 5 ish hour return journey, I have never been good at keeping receipts but is there a reasonable sustenance allowance that can also be claimed? Sorry on another point- the gain will be about £50,000 and I have been advised if I split the property with my wife prior to selling then the tax payable will be roughly £2,000 less is this something that can be done legitimately and purely for this purpose, as I want to avoid tax but certainly not evade it

Hi,
These are not allowable expenses when working out any capital gain - CG15250 - Expenditure: incidental costs of acquisition and disposal.
With regards to transferring to your wife, yes it is allowable - Capital Gains Tax: what you pay it on, rates and allowances
Thank you.