Hi there, this is my first post so please forgive me for diving straight in with a complex CGT question, also for the length of the posting. Unfortunately time isn't on our side and I need some quick, initial advice/thoughts on this situation.Last week my Mum received a tax return out of the blue to cover 2005/06.There are only 2 triggers I can think of that could have triggered the tax return.a) She became 60 years old in that tax year and she started receiving state pension, along with already receiving a small widows pension and a salary from her job (tax office fully aware of this and if I remeber rightly were aware of all her earnings) .b) She sold a 2nd property which was originally her marital home (detail below).I am going on the assumption that the sale of the property has triggered the tax return......especially as it relates to 3 years ago.I guess the easiest thing for me to do is outline a timeline of events which will hopefully make the situation easier to follow:-1981 - Mum & Dad purchase house for c£10,5001988 - Mum & Dad separate (not divorce). Dad, Me & Brother continue to live in house. Mum continues to be joint owner as Dad can't afford mortgage alone.1988 - Mum purchases a 50% share in 2nd property as 'tenant in common'. (Not sure if relevant, but 2nd Property cost c£25k + approx £45k spent on it for renovation/conversion).1995 - Dad dies leaving a will to say he would like his estate to be split between me & my brother. However, because the will wasn't done properly and Mum & Dad were still legally married, everything automatically went to Mum. Deemed house value for probate in 1995 was £45,000. I continue to live in the house (rent free). 1998 - I move out. House empty for a while, then my brother moves in on and off over the couple of years (rent free). 2001 - Mum takes out a mortgage to renovate the house - Replace roof, Double glazing etc. Spent approx £10,000.October 2001 - Rent it out at £550 per month. First 6 months tenant paid rent ok, then started experiencing problems with tenant. Long story short, tenant refused to pay rent, refused to hand back the keys etc etc. Turns out he was a professional 'bad tenant' ended off at a loss, took him to court etc etc - non of the rent was declared as income as Mum ended up worse off through having to pay solicitors fees trying to evict the tenant, recover unpaid rent and fees incurred in making good the damage the tenant had done. Finally got possession of the house back around May 2003.2003 - Property up for sale 'as is', various attempts to sell fell threw.2004 - Took property off market to renovate the house ready for sale again. New Kitchen, carpets & bathroom £5000 spent. December 2005 - Finally completed sale of house for £125,000, however only received £123,000 proceeds as vendor decided to gazunder at the 11th hour and demanded £2k to perform minor decoration etc. Estate agents fees £2570 + solicitor £750. Throughout 2003 - 2005 (sale) Mum had to pay full council tax on the property apart from the first 6 months.So I guess in essence, I need to know is whether there is any capital gains tax arising on the sale of the property. Also where should we go from here? I'd also like to know the 'best' way to present this to the tax man in order to minimalise the tax liability. Can we 'roll over' any gain into her second house? If so, would it be more tax efficient? (The current value of 2nd property is about £180k). She is a basic rate tax payer.At this point I should also point out, after the fiasco with renting out the house, having a bad tenant, going to court and then having trouble selling the house, Mum wanted to put the house behind her and decided that she didn't want any reminders...she threw out most/if not all of the paper work (invoices, receipts, bank statements etc etc) to do with the house. She probably still has the probate stuff but that about it. We do however have pictures of the 'before' and 'after' of the house so we can demonstrate money was spent on the property to renovate it. Is this going to be a problem that she can't provide proof of expenditure?Thanks in advance for ANY advice or guidance you can give, especially one that can give me a rough idea or the liability (if any) that would need to be paid.Apologies - I can't figure out how to add lines in the post to make paragraphs - if someone could let me know, I will go in and edit to post to make it more readible! :-)