I use Sippdeal myself and find them very good.
Their dealing platform seems almost as efficient as HL, and I liked Andy Bell's campaign to help Pensioners' drawdown rights.
Choice of funds is up to you of course.
However if uncertain you can follow the family trusts and most successful companies. Certain Trusts Funds and Companies stand out as long term success stories.
Note advice not to put all eggs in stockmarket basket, but if you are a valuable property owner then you have that diversification already.
There are surveys published which give the relative valuations of various countries property markets compared to long term trend.