Thanks for your question
I am afraid you will be liable to capital gains consideration whether you invest in another property or not.
But assuming you have declared all the rental income to HMRC - you are due private residence relief for the time you lived there and the last 18 months of ownership
So you owned the property (so far) for 105 months and lived there for 46 months - so 46 months plus last 18 months of ownership allow 64 months with private residence relief.
£19,000 gain x 64/105 = £11580 exempt for private residence relief (PPR) and leaves £7420 gain
So then private lettings relief is due (assuming you declared all rental income to HMRC) and this is the lesser of
1) the amount of gain on which PPR is due - so £11580
2) The amount of gain left over after PPR has been applied - so £7420
As the lesser amount is 2) the amount iof gain left over after PPR has been applied - so £7420
Deducted from the reminign gain of £7420 - leaves NIL capital gains to tax.
But I will add even without the private lettings relief ,as the gain was only £7420 and your annual exemption allowance is £11,000 then you still have no taxable gain!
So NIL to pay - you can bank all of the £19,000 tax free. Just ensure you alert HMRC of the sale.