Here is what I think you are looking for
https://www.gov.uk/government/publications/rdr3-statutory-residence-test-srt
There are 4 things going on of which probably only two matter. These are:
1 UK citizenship
2 Domicile
3 UK (legal residency)
4 UK tax according to 3
As Markit says you can spend as long as you like (continuous or otherwise) overseas.
Your citizenship will never be impacted and your domicile is pretty sticky and is unlikely to be impacted unless your permanently settle overseas or chose to move it. I think it would be hard to argue your domicile has changed as the B211 (although it can be renewed) doesn't really confer the right to settle in Indo.
This leaves your residency (legal and tax) which will may be impacted year on year according to the rules set out above with various pros and cons.
Unfortunately it isn't as simple as the 183 days rule as there are some statutory tests that apply in both directions and then its down to ties if this is inconclusive.
The pro of not being (tax) resident is that your income and capital gains are exempt from UK tax whereas remaining resident means your worldwide income is subject to tax and you should in theory fill out an SA tax return.
The cons of not being tax resident is that in theory you are not eligible to use many UK government services ranging from the trivial: not being able to renew or replace your driving licence to not having access to the NHS. In theory many domestic financial services providers, insurance / banks cannot provide you services and in theory your insurances could be void and your bank accounts could theoretically be closed. You'd certainly want to confirm your travel / medical insurance isn't voided. You would also in an extreme circumstance say you sold your UK home whilst being non-resident be subject to CGT on the sale as your are ineligible for the nil-tax band if non-resident.
Hope this helps